configure.ac, common/common.c: search_paths[]: introduce MULTIARCH_TA…

…RGET_ALIAS as/if suggested by compiler [networkupstools#317]

Signed-off-by: Jim Klimov <[email protected]>

common/common.c

@@ -1861,6 +1861,19 @@ static const char * search_paths[] = {
 	LIBDIR,
 	"/usr"LIBDIR,		/* Note: this can lead to bogus strings like */
 	"/usr/local"LIBDIR,	/* "/usr/usr/lib" which would be ignored quickly */
+/* TOTHINK: Should AUTOTOOLS_* specs also be highly preferred?
+ * Currently they are listed after the "legacy" hard-coded paths...
+ */
+#ifdef MULTIARCH_TARGET_ALIAS
+# ifdef BUILD_64
+	"/usr/lib/64/" MULTIARCH_TARGET_ALIAS,
+	"/usr/lib64/" MULTIARCH_TARGET_ALIAS,
+	"/lib/64/" MULTIARCH_TARGET_ALIAS,
+	"/lib64/" MULTIARCH_TARGET_ALIAS,
+# endif	/* MULTIARCH_TARGET_ALIAS && BUILD_64 */
+	"/usr/lib/" MULTIARCH_TARGET_ALIAS,
+	"/lib/" MULTIARCH_TARGET_ALIAS,
+#endif	/* MULTIARCH_TARGET_ALIAS */
 #ifdef BUILD_64
 	/* Fall back to explicit preference of 64-bit paths as named on some OSes */
 	"/usr/lib/64",

configure.ac

@@ -3860,6 +3860,14 @@ if test -n "${target_cpu}" -a -n "${target_os}" ; then
 	NUT_REPORT_TARGET(AUTOTOOLS_TARGET_SHORT_ALIAS, "${target_cpu}-${target_os}", [host OS short spec we built for])
 fi
 
+AC_MSG_CHECKING([whether compiler suggests a MULTIARCH value])
+dnl Recent GCC generally supports this call, although it often returns empty
+dnl Some versions of CLANG also have it, others reject the unknown CLI switch
+compiler_multiarch="`${CC} -print-multiarch 2>/dev/null`" || compiler_multiarch=""
+if test -n "${compiler_multiarch}" ; then
+	NUT_REPORT_TARGET(MULTIARCH_TARGET_ALIAS, "${compiler_multiarch}", [host multiarch spec we build for (as suggested by compiler being used)])
+fi
+
 dnl ----------------------------------------------------------------------
 dnl Check the user and group to run as last, so we can use the paths configured
 dnl above as data sources for default values if building an in-place replacement