-pendantic is too pendantic

Many system headers have warnings when compiled with this flag.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-By: Uli Schlachter <psychon@znc.in>

configure.ac

@@ -128,7 +128,7 @@ xcbincludedir='${includedir}/xcb'
 AC_SUBST(xcbincludedir)
 
 if  test "x$GCC" = xyes ; then
-    CWARNFLAGS="-Wall -pedantic -Wpointer-arith \
+    CWARNFLAGS="-Wall -Wpointer-arith \
 		-Wstrict-prototypes -Wmissing-declarations -Wnested-externs"
 else
     AC_CHECK_DECL([__SUNPRO_C], [SUNCC="yes"], [SUNCC="no"])