[MacPorts] #68659: mips-elf-gcc @3.4.6_0: fails to build due to implicit declaration of abort()

[MacPorts]

#68659: mips-elf-gcc @3.4.6_0: fails to build due to implicit declaration of
abort()
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  Reporter:  nneonneo  |      Owner:  (none)
      Type:  defect    |     Status:  new
  Priority:  Normal    |  Milestone:
 Component:  ports     |    Version:  2.8.1
Resolution:            |   Keywords:
      Port:            |
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Comment (by nneonneo):

 Got a successful build with the following changes:

 - Configure with `CC='/usr/bin/clang -Wno-error=implicit-function-
 declaration'` and with `CXXFLAGS='-Os
 -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX13.sdk'` (note:
 *no* `-stdlib=libc++` in CXXFLAGS!)
 - Build with `CPATH` unset
 - I made a few other small changes, but those shouldn't have been required
 to actually make things work.

 We need `-Wno-error=implicit-function-declaration` to get `STDC_HEADERS`
 defined and fix many errors while building this old GCC; notably, we
 cannot put the flag in `CFLAGS` because otherwise it would be picked up
 while cross-compiling the target libraries, and the target GCC doesn't
 understand this flag. Similarly, we cannot have `-stdlib=libc++` (and
 probably shouldn't even have `-isysroot`) in CXXFLAGS as the target GCC
 doesn't understand `-stdlib`. More generally, we should probably be
 configuring the host and target separately so we can have different
 CFLAGS/CXXFLAGS for them.

 We also need to unset CPATH because it gets picked up during cross-
 compilation, and will cause the compiler to look for target headers in
 /opt/local/include which breaks the build.

-- 
Ticket URL: <https://trac.macports.org/ticket/68659#comment:2>
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