I'm having problems building gcc under cygwin. I was informed that Cygwin has gcc-2.95.2-6 and so it isn't necessary to do a 'make bootstrap'. I did a normal make, but I am still not able to build it. This is what I have done:   my gcc source is in /srcdir/gcc-2.95.3 my build directory is /build   export MAKE_MODE=UNIX /srcdir/gcc-2.95.3/configure --prefix=/usr --with-gnu-as --with-gnu-ld --enable-threads=posix 2>&1 | tee configure.out make -w all-gcc install-gcc LANGUAGES="c c++ java" 2>&1 | tee make.out   The make fails with the following error message:   /build/gcc/xgcc -B/build/gcc/ -B/usr/i686-pc-cygwin32/bin/ -I/usr/i686-pc-cygwin32/include -O2 -I/srcdir/gcc-2.95.3/gcc/../winsup/include -DIN_GCC -g -O2 -I./include -g1 -DHAVE_GTHR_DEFAULT -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED -fexceptions -I. -I/srcdir/gcc-2.95.3/gcc -I/srcdir/gcc-2.95.3/gcc/config -I/srcdir/gcc-2.95.3/gcc/../include -c \ -DL${name} /srcdir/gcc-2.95.3/gcc/libgcc2.c -o ${name}.o; \ if [ $? -eq 0 ] ; then true; else exit 1; fi; \ ar rc tmplibgcc2.a ${name}.o; \ rm -f ${name}.o; \ done _eh In file included from gthr-default.h:1, from /srcdir/gcc-2.95.3/gcc/gthr.h:98, from /srcdir/gcc-2.95.3/gcc/libgcc2.c:3034: /srcdir/gcc-2.95.3/gcc/gthr-posix.h:40: parse error before `__gthread_once_t' /srcdir/gcc-2.95.3/gcc/gthr-posix.h:40: warning: data definition has no type or storage class /srcdir/gcc-2.95.3/gcc/gthr-posix.h:78: parse error before `*' /srcdir/gcc-2.95.3/gcc/gthr-posix.h:78: parse error before `)' /srcdir/gcc-2.95.3/gcc/gthr-posix.h: In function `__gthread_key_create': /srcdir/gcc-2.95.3/gcc/gthr-posix.h:89: too many arguments to function `pthread_key_create' /srcdir/gcc-2.95.3/gcc/gthr-posix.h: In function `__gthread_key_dtor': /srcdir/gcc-2.95.3/gcc/gthr-posix.h:97: incompatible type for argument 1 of `pthread_setspecific' /srcdir/gcc-2.95.3/gcc/gthr-posix.h: In function `__gthread_key_delete': /srcdir/gcc-2.95.3/gcc/gthr-posix.h:105: incompatible type for argument 1 of `pthread_key_delete' /srcdir/gcc-2.95.3/gcc/gthr-posix.h: In function `__gthread_getspecific': /srcdir/gcc-2.95.3/gcc/gthr-posix.h:111: incompatible type for argument 1 of `pthread_getspecific' /srcdir/gcc-2.95.3/gcc/gthr-posix.h: In function `__gthread_setspecific': /srcdir/gcc-2.95.3/gcc/gthr-posix.h:117: incompatible type for argument 1 of `pthread_setspecific' /srcdir/gcc-2.95.3/gcc/libgcc2.c: In function `eh_context_initialize': /srcdir/gcc-2.95.3/gcc/libgcc2.c:3171: syntax error before `once' /srcdir/gcc-2.95.3/gcc/libgcc2.c:3175: `once' undeclared (first use in this function) /srcdir/gcc-2.95.3/gcc/libgcc2.c:3175: (Each undeclared identifier is reported only once /srcdir/gcc-2.95.3/gcc/libgcc2.c:3175: for each function it appears in.) make[1]: *** [libgcc2.a] Error 1 make[1]: Leaving directory `/build/gcc' make: *** [all-gcc] Error 2 make: Leaving directory `/build'   I am not sure what this means. This is the first time I am trying to compile gcc. Any help would be appreciated. Thanks!   Vivin