AIX: build failure on AIX 7.1

There's no xlc/xlC on my AIX 7.1. I got gcc/g++ from http://www.oss4aix.org/download/everything/RPMS/.

# g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/opt/freeware/libexec/gcc/powerpc-ibm-aix7.1.0.0/6.3.0/lto-wrapper
Target: powerpc-ibm-aix7.1.0.0
Configured with: ../gcc-6.3.0/configure --with-as=/usr/bin/as --with-ld=/usr/bin/ld --enable-languages=c,c++,fortran --prefix=/opt/freeware --mandir=/opt/freeware/man --infodir=/opt/freeware/info --enable-version-specific-runtime-libs --disable-nls --enable-decimal-float=dpd --with-cloog=no --with-ppl=no --disable-libstdcxx-pch --enable-__cxa_atexit --enable-bootstrap --host=powerpc-ibm-aix7.1.0.0
Thread model: aix
gcc version 6.3.0 (GCC)
# git clone https://gitlab.kitware.com/cmake/cmake.git
# cd cmake
# git log |head -n 1
commit fdf5d0a04bc065623402944234e58b897bac5ac9
# ./bootstrap
# gmake
[ 91%] Linking CXX executable ../bin/cmake
ld: 0711-317 ERROR: Undefined symbol: .ceilf
ld: 0711-345 Use the -bloadmap or -bnoquiet option to obtain more information.
collect2: error: ld returned 8 exit status
gmake[2]: *** [Source/CMakeFiles/cmake.dir/build.make:127: bin/cmake] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:2196: Source/CMakeFiles/cmake.dir/all] Error 2
gmake: *** [Makefile:166: all] Error 2

I notice that /usr/bin/ld links to /usr/ccs/bin/ld. However changing it to /opt/freeware/bin/gld doesn't help.