${target} in configure.ac should be the canonical target, so that for
example, someone configuring with --target=x86_64-linux will match
x86_64-*-linux*.
* configure.ac: Invoke AC_CANONICAL_TARGET.
* libcollector/configure.ac: Likewise.
* Makefile.in: Regenerate.
* configure: Regenerate.
* doc/Makefile.in: Regenerate.
* gp-display-html/Makefile.in: Regenerate.
* libcollector/Makefile.in: Regenerate.
* libcollector/configure: Regenerate.
* src/Makefile.in: Regenerate.
Use -Wno-nonnull-compare only if it is supported.
PR gprof/28969
* libcollector/Makefile.am (AM_CFLAGS): Replace
-Wno-nonnull-compare with GPROFNG_NO_NONNULL_COMPARE_CFLAGS.
* libcollector/configure.ac (GPROFNG_NO_NONNULL_COMPARE_CFLAGS):
New AC_SUBST for -Wno-nonnull-compare.
* libcollector/Makefile.in: Regenerate.
* libcollector/aclocal.m4: Likewise.
* libcollector/configure: Likewise.