configure: Don't use -pedantic.

Else, GCC will complain about "ISO C forbids conversion of object pointer to
function pointer type", even for casting function points to or from void
pointers. This is allowed by POSIX, though, and required, for example, for
dlsym() to work.

configure.ac

@@ -108,7 +108,7 @@ if test "x$enable_standards" = "xyes"; then
 	dnl strict standards compliance a bit to work around this.
 	AC_DEFINE([_BSD_SOURCE], 1, [Define to enable 4.3BSD support.])
 
-	for flag in -std=c99 -pedantic; do
+	for flag in -std=c99; do
 		AC_MSG_CHECKING([whether $CC accepts $flag])
 
 		if test_cc_flags $flag; then