MinGW: link as terminal server aware

Whith Windows 2000, Microsoft introduced a flag to the PE header to mark executables as
"terminal server aware". Windows terminal servers provide a redirected Windows directory and
redirected registry hives when launching legacy applications without this flag set. Since we
do not use any INI files in the Windows directory and don't write to the registry, we don't
need  this additional preparation. Telling the OS that we don't need this should provide
slightly improved startup times in terminal server environments.

When building for supported Windows Versions with MSVC the /TSAWARE linker flag is
automatically set, but MinGW requires us to set the --tsaware flag manually.

This partially addresses git-for-windows#3935.

Signed-off-by: Matthias Aßhauer <mha1993@live.de>

config.mak.uname

@@ -666,7 +666,7 @@ ifeq ($(uname_S),MINGW)
 	DEFAULT_HELP_FORMAT = html
 	HAVE_PLATFORM_PROCINFO = YesPlease
 	CSPRNG_METHOD = rtlgenrandom
-	BASIC_LDFLAGS += -municode
+	BASIC_LDFLAGS += -municode -Wl,--tsaware
 	COMPAT_CFLAGS += -DNOGDI -Icompat -Icompat/win32
 	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
 	COMPAT_OBJS += compat/mingw.o compat/winansi.o \