gcc6 and libgcc fail to build on Tiger i386 due to -ldylib1.10.5.o not found. Fixes to repair.

[kencu (Ken)]

I'll start off by admitting up front that this is of interest to very few. If you have a Tiger VM you might possibly be interested in this. I don't expect anyone to fix this. My apologies to those who find this noise on the system.

Tiger PPC builds gcc6 and libgcc without any trouble. However, the build on Tiger i386 fails with the above error.

It appears that the essential issue is that the environment variables don't get passed through to all the builds of the libraries and second and third stages. During the configure and make stages, no -mmacosx-version-min is specified on the compile line. It appears that the logic in the gcc6 darwin configuration files defaults to putting -mmacosx-version-min=10.5 if it sees no other, and so when this builds on Tiger 10.4, the proper 10.5 libraries are not found. Why this occurs on intel i386 and not on PPC is a mystery to me at present. I didn't try x86_64 on Tiger.

The fix is to get -mmacosx-version-min=10.4 onto all the compile lines somehow. GCC has a lot of tools to do this, and there are variables like BOOT_CFLAGS and STAGE1_CFLAGS and many more to help force these compiles to proceed. I tried adjusting these things in the portfile, adding them to the build.args in various ways, but in the end, I did not figure it out. It doesn't help that gcc6 takes hours to build, so test cycles are long.

I wound up manually editing the Makefile in the build directory, which works correctly. I'm sure there is a more elegant way to do this, but I ran out patience after a suitable number of attempts.

To build it, I first ran sudo port configure libgcc, and then tried various things, ultimately editing the work/build/Makefile in four places like so:

 # Flags to pass to stage2 and later makes.  They are defined
 # here so that they can be overridden by Makefile fragments.
-BOOT_CFLAGS= -g -O2
+BOOT_CFLAGS= -g -O2 -mmacosx-version-min=10.4


 CFLAGS = -pipe -Os
-LDFLAGS = -L/opt/local/lib -Wl,-headerpad_max_install_names
+LDFLAGS = -L/opt/local/lib -Wl,-headerpad_max_install_names -mmacosx-version-min=10.4


-STAGE1_CFLAGS = -g
+STAGE1_CFLAGS = -g -mmacosx-version-min=10.4
 STAGE1_CHECKING = --enable-checking=yes


-CFLAGS_FOR_TARGET = -g -O2 -pipe -Os
-CXXFLAGS_FOR_TARGET = -g -O2 -pipe -Os
+CFLAGS_FOR_TARGET = -g -O2 -pipe -Os -mmacosx-version-min=10.4
+CXXFLAGS_FOR_TARGET = -g -O2 -pipe -Os -mmacosx-version-min=10.4

After that built, I ran sudo port configure gcc6, made the same edits in work/build/Makefile as above, and gcc6 built through to completion.

You would think that these could have been passed in to the gcc6 build process without editing the Makefile, and I'm sure it should be able to be so, but none of what I tried worked.

In addition to these flags, there was one minor patch needed to /libcilkrts/runtime/sysdep-unix.c, to make it work on Tiger Intel, which I have included here. This patch was not needed on Tiger PPC.

I also made one enhancement to libgcc, to make it default to always building software that is ABI compatible with the gcc4 ABI, to help make it less likely to have issues with gcc42's libstdc++ on Tiger. This is accomplished with the following bit:

variant usegcc4abi description {default to gcc4-compatible ABI} {
	configure.args-append --with-default-libstdcxx-abi=gcc4-compatible
}

I'll attach the Portfile that worked for gcc 6.02 , and the Tiger patchfile, for any other intrepid software archeologists. Sorry for any glaring errors I made.

In the end, gcc and libgcc appear to work as expected. I'm hoping to get them both built +universal if possible, so that I can compile software on the VM and use it on Tiger PPC.

[kencu (Ken)]

working gcc6 / libgcc Portfile for Tiger i386

[kencu (Ken)]

patchfile for sysdep-unix.c for Tiger i386

[kencu (Ken)]

The title should read -ldylib1.10.5.o not found, for anyone who is searching for this error with google like I was.

[kencu (Ken)]

closed by: <​https://github.com/macports/macports-ports/commit/b8a82fd518385869d68c0b4e1e96af73353af5d3>