+MISSING=`cd $ac_aux_dir && ${PWDCMD-pwd}`/missing
+AC_CHECK_PROGS([ACLOCAL], [aclocal], [$MISSING aclocal])
+AC_CHECK_PROGS([AUTOCONF], [autoconf], [$MISSING autoconf])
+AC_CHECK_PROGS([AUTOHEADER], [autoheader], [$MISSING autoheader])
+
+# Figure out what compiler warnings we can enable.
+# See config/warnings.m4 for details.
+
+ACX_PROG_CC_WARNING_OPTS([-W -Wall -Wwrite-strings -Wstrict-prototypes \
+ -Wmissing-prototypes -Wold-style-definition \
+ -Wmissing-format-attribute])
+ACX_PROG_CC_WARNING_ALMOST_PEDANTIC([-Wno-long-long])
+
+# Only enable with --enable-werror-always until existing warnings are
+# corrected.
+ACX_PROG_CC_WARNINGS_ARE_ERRORS([manual])
+
+# Dependency checking.
+ZW_CREATE_DEPDIR
+ZW_PROG_COMPILER_DEPENDENCIES([CC])
+