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win32: add a helper to run git.exe without a foreground window
On Windows, there are two kinds of executables, console ones and non-console ones. Git's executables are all console ones. When launching the former e.g. in a scheduled task, a CMD window pops up. This is not what we want for the tasks installed via the `git maintenance` command. To work around this, let's introduce `headless-git.exe`, which is a non-console program that does _not_ pop up any window. All it does is to re-launch `git.exe`, suppressing that console window, passing through all command-line arguments as-are. Helped-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Helped-by: Yuyi Wang <Strawberry_Str@hotmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
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‎Makefile‎

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Original file line numberDiff line numberDiff line change
@@ -2777,6 +2777,13 @@ compat/nedmalloc/nedmalloc.sp compat/nedmalloc/nedmalloc.o: EXTRA_CPPFLAGS = \
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compat/nedmalloc/nedmalloc.sp: SP_EXTRA_FLAGS += -Wno-non-pointer-null
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endif
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headless-git.o: compat/win32/headless.c GIT-CFLAGS
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$(QUIET_CC)$(CC) $(ALL_CFLAGS) $(COMPAT_CFLAGS) \
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-fno-stack-protector -o $@ -c -Wall -Wwrite-strings $<
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headless-git$X: headless-git.o git.res GIT-LDFLAGS
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$(QUIET_LINK)$(CC) $(ALL_CFLAGS) $(ALL_LDFLAGS) -mwindows -o $@ $< git.res
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git-%$X: %.o GIT-LDFLAGS $(GITLIBS)
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$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS)
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@@ -3650,6 +3657,7 @@ clean: profile-clean coverage-clean cocciclean
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$(RM) po/git.pot po/git-core.pot
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$(RM) git.res
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$(RM) $(OBJECTS)
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$(RM) headless-git.o
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$(RM) $(LIB_FILE) $(XDIFF_LIB) $(REFTABLE_LIB) $(REFTABLE_TEST_LIB)
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$(RM) $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) $(OTHER_PROGRAMS)
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$(RM) $(TEST_PROGRAMS)
@@ -3678,6 +3686,7 @@ endif
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$(RM) GIT-SCRIPT-DEFINES GIT-PERL-DEFINES GIT-PERL-HEADER GIT-PYTHON-VARS
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ifdef MSVC
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$(RM) $(patsubst %.o,%.o.pdb,$(OBJECTS))
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$(RM) headless-git.o.pdb
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$(RM) $(patsubst %.exe,%.pdb,$(OTHER_PROGRAMS))
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$(RM) $(patsubst %.exe,%.ilk,$(OTHER_PROGRAMS))
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$(RM) $(patsubst %.exe,%.iobj,$(OTHER_PROGRAMS))

‎compat/win32/headless.c‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,115 @@
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/*
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* headless Git - run Git without opening a console window on Windows
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*/
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#define STRICT
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#define WIN32_LEAN_AND_MEAN
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#define UNICODE
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#define _UNICODE
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#include <windows.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <wchar.h>
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/*
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* If `dir` contains the path to a Git exec directory, extend `PATH` to
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* include the corresponding `bin/` directory (which is where all those
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* `.dll` files needed by `git.exe` are, on Windows).
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*/
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static int extend_path(wchar_t *dir, size_t dir_len)
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{
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const wchar_t *suffix = L"\\libexec\\git-core";
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size_t suffix_len = wcslen(suffix);
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wchar_t *env;
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DWORD len;
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if (dir_len < suffix_len)
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return 0;
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dir_len -= suffix_len;
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if (memcmp(dir + dir_len, suffix, suffix_len * sizeof(wchar_t)))
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return 0;
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len = GetEnvironmentVariableW(L"PATH", NULL, 0);
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if (!len)
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return 0;
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env = _alloca((dir_len + 5 + len) * sizeof(wchar_t));
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wcsncpy(env, dir, dir_len);
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wcscpy(env + dir_len, L"\\bin;");
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if (!GetEnvironmentVariableW(L"PATH", env + dir_len + 5, len))
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return 0;
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SetEnvironmentVariableW(L"PATH", env);
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return 1;
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}
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int WINAPI wWinMain(_In_ HINSTANCE instance,
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_In_opt_ HINSTANCE previous_instance,
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_In_ LPWSTR command_line, _In_ int show)
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{
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wchar_t git_command_line[32768];
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size_t size = sizeof(git_command_line) / sizeof(wchar_t);
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const wchar_t *needs_quotes = L"";
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int slash = 0, i;
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STARTUPINFO startup_info = {
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.cb = sizeof(STARTUPINFO),
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.dwFlags = STARTF_USESHOWWINDOW,
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.wShowWindow = SW_HIDE,
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};
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PROCESS_INFORMATION process_info = { 0 };
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DWORD creation_flags = CREATE_UNICODE_ENVIRONMENT |
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CREATE_NEW_CONSOLE | CREATE_NO_WINDOW;
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DWORD exit_code;
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/* First, determine the full path of argv[0] */
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for (i = 0; _wpgmptr[i]; i++)
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if (_wpgmptr[i] == L' ')
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needs_quotes = L"\"";
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else if (_wpgmptr[i] == L'\\')
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slash = i;
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if (slash >= size - 11)
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return 127; /* Too long path */
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/* If it is in Git's exec path, add the bin/ directory to the PATH */
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extend_path(_wpgmptr, slash);
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/* Then, add the full path of `git.exe` as argv[0] */
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i = swprintf_s(git_command_line, size, L"%ls%.*ls\\git.exe%ls",
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needs_quotes, slash, _wpgmptr, needs_quotes);
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if (i < 0)
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return 127; /* Too long path */
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if (*command_line) {
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/* Now, append the command-line arguments */
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i = swprintf_s(git_command_line + i, size - i,
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L" %ls", command_line);
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if (i < 0)
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return 127;
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}
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startup_info.hStdInput = GetStdHandle(STD_INPUT_HANDLE);
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startup_info.hStdOutput = GetStdHandle(STD_OUTPUT_HANDLE);
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startup_info.hStdError = GetStdHandle(STD_ERROR_HANDLE);
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if (!CreateProcess(NULL, /* infer argv[0] from the command line */
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git_command_line, /* modified command line */
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NULL, /* inherit process handles? */
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NULL, /* inherit thread handles? */
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FALSE, /* handles inheritable? */
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creation_flags,
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NULL, /* use this process' environment */
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NULL, /* use this process' working directory */
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&startup_info, &process_info))
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return 129; /* could not start */
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WaitForSingleObject(process_info.hProcess, INFINITE);
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if (!GetExitCodeProcess(process_info.hProcess, &exit_code))
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exit_code = 130; /* Could not determine exit code? */
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CloseHandle(process_info.hProcess);
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CloseHandle(process_info.hThread);
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return (int)exit_code;
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}

‎config.mak.uname‎

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Original file line numberDiff line numberDiff line change
@@ -527,6 +527,8 @@ else
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endif
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X = .exe
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EXTRA_PROGRAMS += headless-git$X
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compat/msvc.o: compat/msvc.c compat/mingw.c GIT-CFLAGS
531533
endif
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ifeq ($(uname_S),Interix)
@@ -679,6 +681,7 @@ ifeq ($(uname_S),MINGW)
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RC = windres -O coff
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NATIVE_CRLF = YesPlease
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X = .exe
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EXTRA_PROGRAMS += headless-git$X
682685
ifneq (,$(wildcard ../THIS_IS_MSYSGIT))
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htmldir = doc/git/html/
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prefix =

‎contrib/buildsystems/CMakeLists.txt‎

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@@ -738,6 +738,15 @@ if(WIN32)
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else()
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message(FATAL_ERROR "Unhandled compiler: ${CMAKE_C_COMPILER_ID}")
740740
endif()
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add_executable(headless-git ${CMAKE_SOURCE_DIR}/compat/win32/headless.c)
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if(CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_C_COMPILER_ID STREQUAL "Clang")
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target_link_options(headless-git PUBLIC -municode -Wl,-subsystem,windows)
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elseif(CMAKE_C_COMPILER_ID STREQUAL "MSVC")
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target_link_options(headless-git PUBLIC /NOLOGO /ENTRY:wWinMainCRTStartup /SUBSYSTEM:WINDOWS)
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else()
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message(FATAL_ERROR "Unhandled compiler: ${CMAKE_C_COMPILER_ID}")
749+
endif()
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elseif(UNIX)
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target_link_libraries(common-main pthread rt)
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endif()

‎contrib/buildsystems/Generators/Vcxproj.pm‎

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Original file line numberDiff line numberDiff line change
@@ -76,7 +76,7 @@ sub createProject {
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my $libs_release = "\n ";
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my $libs_debug = "\n ";
79-
if (!$static_library) {
79+
if (!$static_library && $name ne 'headless-git') {
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$libs_release = join(";", sort(grep /^(?!libgit\.lib|xdiff\/lib\.lib|vcs-svn\/lib\.lib|reftable\/libreftable\.lib)/, @{$$build_structure{"$prefix${name}_LIBS"}}));
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$libs_debug = $libs_release;
8282
$libs_debug =~ s/zlib\.lib/zlibd\.lib/g;
@@ -254,7 +254,7 @@ EOM
254254
print F << "EOM";
255255
</ItemGroup>
256256
EOM
257-
if (!$static_library || $target =~ 'vcs-svn' || $target =~ 'xdiff') {
257+
if ((!$static_library || $target =~ 'vcs-svn' || $target =~ 'xdiff') && !($name =~ /headless-git/)) {
258258
my $uuid_libgit = $$build_structure{"LIBS_libgit_GUID"};
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my $uuid_libreftable = $$build_structure{"LIBS_reftable/libreftable_GUID"};
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my $uuid_xdiff_lib = $$build_structure{"LIBS_xdiff/lib_GUID"};

‎contrib/buildsystems/engine.pl‎

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@@ -370,6 +370,7 @@ sub handleLinkLine
370370
# exit(1);
371371
foreach (@objfiles) {
372372
my $sourcefile = $_;
373+
$sourcefile =~ s/^headless-git\.o$/compat\/win32\/headless.c/;
373374
$sourcefile =~ s/\.o$/.c/;
374375
$sourcefile =~ s/\.res$/.rc/;
375376
push(@sources, $sourcefile);

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