Current ghc spits warnings time to time:

<no location info>:
    Warning: Couldn't figure out linker information!
             Make sure you're using GNU gcc, or clang

It's because my default locale is LANG=ru_RU.UTF-8 [1]

...
gcc версия 4.8.2 (Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest)

versus LANG=C

...
gcc version 4.8.2 (Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest)

[1]:

$ gcc -v
Используются внутренние спецификации.
COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.2/gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.8.2/lto-wrapper
Целевая архитектура: x86_64-pc-linux-gnu
Параметры конфигурации: /subvolumes/var_tmp/portage/sys-devel/gcc-4.8.2-r1/work/gcc-4.8.2/configure --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.2 --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/info --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4 --with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/python --enable-languages=c,c++,fortran --enable-obsolete --enable-secureplt --disable-werror --with-system-zlib --enable-nls --without-included-gettext --enable-checking=release --with-bugurl=https://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest' --enable-libstdcxx-time --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --enable-multilib --with-multilib-list=m32,m64 --disable-altivec --disable-fixed-point --enable-targets=all --disable-libgcj --enable-libgomp --disable-libmudflap --disable-libssp --enable-lto --without-cloog
Модель многопоточности: posix
gcc версия 4.8.2 (Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest)

[2]: While LANG=C output:

$ LANG=C gcc -v
Using built-in specs.
COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.2/gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.8.2/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /subvolumes/var_tmp/portage/sys-devel/gcc-4.8.2-r1/work/gcc-4.8.2/configure --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.2 --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/info --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4 --with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/python --enable-languages=c,c++,fortran --enable-obsolete --enable-secureplt --disable-werror --with-system-zlib --enable-nls --without-included-gettext --enable-checking=release --with-bugurl=https://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest' --enable-libstdcxx-time --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --enable-multilib --with-multilib-list=m32,m64 --disable-altivec --disable-fixed-point --enable-targets=all --disable-libgcj --enable-libgomp --disable-libmudflap --disable-libssp --enable-lto --without-cloog
Thread model: posix
gcc version 4.8.2 (Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest)