I'm trying to install gcc 4.5.3 (alongside the default 4.6.x) on my desktop running Fedora 15. I've tried different configure settings, but most recently: ../gcc-4.5.3/configure CC=gcc CXX=g++ --prefix=/opt/gcc4.5.3/gcc453 --program-suffix=4.5.3 --disable-multilibs --disable-shared --enable-threads=posix --enable-build-with-cxx When I try to make gcc I get the following error: make -j 4 bootstrap g++ -I../../gcc-4.5.3/libcpp -I. -I../../gcc-4.5.3/libcpp/../include -I../../gcc-4.5.3/libcpp/include -g -W -Wall -Wwrite-strings -Wmissing-format-attribute -pedantic -Wno-long-long -I../../gcc-4.5.3/libcpp -I. -I../../gcc-4.5.3/libcpp/../include -I../../gcc-4.5.3/libcpp/include -c -o directives-only.o -MT directives-only.o -MMD -MP -MF .deps/directives-only.Tpo ../../gcc-4.5.3/libcpp/directives-only.c yes In file included from ../../gcc-4.5.3/libcpp/system.h:341:0, from ../../gcc-4.5.3/libcpp/charset.c:22: ../../gcc-4.5.3/libcpp/../include/libiberty.h:106:36: error: new declaration ‘char* basename(const char*)’ /usr/include/string.h:603:28: error: ambiguates old declaration ‘const char* basename(const char*)’ In file included from ../../gcc-4.5.3/libcpp/system.h:341:0, from ../../gcc-4.5.3/libcpp/directives.c:24: ../../gcc-4.5.3/libcpp/../include/libiberty.h:106:36: error: new declaration ‘char* basename(const char*)’ /usr/include/string.h:603:28: error: ambiguates old declaration ‘const char* basename(const char*)’ checking whether getopt is declared... In file included from ../../gcc-4.5.3/libcpp/system.h:341:0, from ../../gcc-4.5.3/libcpp/directives-only.c:21: ../../gcc-4.5.3/libcpp/../include/libiberty.h:106:36: error: new declaration ‘char* basename(const char*)’ /usr/include/string.h:603:28: error: ambiguates old declaration ‘const char* basename(const char*)’ make[3]: *** [directives-only.o] Error 1 make[3]: *** Waiting for unfinished jobs.... make[3]: *** [directives.o] Error 1 make[3]: *** [charset.o] Error 1 make[3]: Leaving directory `/opt/gcc4.5.3/BUILD/libcpp' make[2]: *** [all-stage1-libcpp] Error 2 make[2]: *** Waiting for unfinished jobs.... Is there a fix for this? Dan