fix Issue 303: libgphobos.spec not found linking stage2

[ibuclaw]

1. Error libgphobos.spec not found.

gdc: error: libgphobos.spec: No such file or directory

Link command was missing -B option to prev-target/libphobos/src in POSTSTAGE1_HOST_EXPORTS, and so it was using the host installed copy if found. The error occurs if libgphobos.spec is not found on the host either.

Bug fix: https://bugzilla.gdcproject.org/show_bug.cgi?id=303

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2. Error undefined references to recently added druntime symbols.

d: d/dmodule.o:(.data.rel.ro._D3dmd5parse__T6ParserTS3dmd10astcodegen10ASTCodegenZQBm6__vtblZ[_D3dmd5parse__T6ParserTS3dmd10astcodegen10ASTCodegenZQBm6__vtblZ]+0x18): undefined reference to `_D6object6Object5opCmpMFCQqZi'
ld: d/dmodule.o:(.data.rel.ro._D3dmd5parse__T6ParserTS3dmd10astcodegen10ASTCodegenZQBm6__vtblZ[_D3dmd5parse__T6ParserTS3dmd10astcodegen10ASTCodegenZQBm6__vtblZ]+0x20): undefined reference to `_D6object6Object8opEqualsMFCQtZb'
ld: d/filename.o: in function `FileName::searchPath(Array<char const*>*, char const*, bool)':
gcc/d/dmd/root/filename.d:611: undefined reference to `_D4core3sys5posixQk4stat7S_ISDIRFNbNikZb'
ld: gcc/d/dmd/root/filename.d:611: undefined reference to `_D4core3sys5posixQk4stat7S_ISDIRFNbNikZb'
ld: d/filename.o: in function `FileName::exists(char const*)':
gcc/d/dmd/root/filename.d:611: undefined reference to `_D4core3sys5posixQk4stat7S_ISDIRFNbNikZb'
ld: d/filename.o: in function `FileName::safeSearchPath(Array<char const*>*, char const*)':
gcc/d/dmd/root/filename.d:611: undefined reference to `_D4core3sys5posixQk4stat7S_ISDIRFNbNikZb'
ld: d/filename.o: in function `FileName::ensurePathExists(char const*) [clone .localalias.0]':
gcc/d/dmd/root/filename.d:611: undefined reference to `_D4core3sys5posixQk4stat7S_ISDIRFNbNikZb'

Link command was missing -L option to prev-target/libphobos/libdruntime/.libs in POSTSTAGE1_HOST_EXPORTS, and so it was linking against the host installed copy of libgdruntime, which is a different version to the one being built.

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3. Stage 2 fails to build after merging Update to dmd master 20180824 #704 (if I understand write) due to changes to __c_long definition.

gcc/d/dmd/root/longdouble.d:30:5: note: ‘dmd.root.longdouble.longdouble.__ctor(T)(T r)’
     this(T)(T r)
     ^
gcc/d/dmd/dcast.d:381:52: error: cannot cast expression ‘cast(long)value’ of type ‘long’ to ‘longdouble’
                 const f = cast(T) cast(sinteger_t) value;
                                                    ^
gcc/d/dmd/dcast.d:459:22: error: template instance ‘dmd.dcast.implicitConvTo.ImplicitConvTo.visit.isLosslesslyConvertibleToFP!(longdouble)’ error instantiating
                 if (!isLosslesslyConvertibleToFP!real_t)
                      ^

See: dlang/dmd#8632
Bug fix: https://bugzilla.gdcproject.org/show_bug.cgi?id=301

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4. Fix gagged warning discovered when debugging [3].

gcc/d/dmd/root/longdouble.d:28:1: anachronism: ‘dmd.root.longdouble.longdouble.opAssign’ called with argument types ‘(longdouble)’ matches both:
   gcc/d/dmd/root/longdouble.d:36:16:     ‘dmd.root.longdouble.longdouble.opAssign!(longdouble).opAssign(longdouble r)’
and:
   gcc/d/dmd/root/longdouble.d:43:16:     ‘dmd.root.longdouble.longdouble.opAssign!(longdouble).opAssign(longdouble r)’
28 | struct longdouble
   | ^

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5. Error cannot find libstdc++

ld: cannot find -lstdc++
collect2: error: ld returned 1 exit status
make[3]: *** [../../gcc/d/Make-lang.in:191: cc1d] Error 1

Link command was missing -L option to prev-target/libstdc++-v3/src/.libs in POSTSTAGE1_HOST_EXPORTS, and so it was using the host installed copy if found. The error occurs if libstdc++ is not found on the host.

[MoritzMaxeiner]

Works for me