multiarch support for non-glibc linux systems

Current multiarch directory name is always *-linux-gnu* on linux,
this patch configures different names for uclibc and musl targets.

2017-06-28  Szabolcs Nagy  <szabolcs.nagy@arm.com>

	* config.gcc (*-linux-musl*): Add t-musl tmake_file.
	(*-linux-uclibc*): Add t-uclibc tmake_file.
	* config/t-musl: New.
	* config/t-uclibc: New.

From-SVN: r249745

gcc/ChangeLog

+2017-06-28  Szabolcs Nagy  <szabolcs.nagy@arm.com>
+
+	* config.gcc (*-linux-musl*): Add t-musl tmake_file.
+	(*-linux-uclibc*): Add t-uclibc tmake_file.
+	* config/t-musl: New.
+	* config/t-uclibc: New.
+
 2017-06-28  Richard Earnshaw  <rearnsha@arm.com>
 
 	* config/arm/parsecpu.awk (profile): Parse new keyword in an arch

gcc/config.gcc

@@ -3112,6 +3112,16 @@ powerpc*-*-* | rs6000-*-*)
 	tm_file="${tm_file} ${cpu_type}/option-defaults.h"
 esac
 
+# non-glibc systems
+case ${target} in
+*-linux-musl*)
+	tmake_file="${tmake_file} t-musl"
+	;;
+*-linux-uclibc*)
+	tmake_file="${tmake_file} t-uclibc"
+	;;
+esac
+
 # Build mkoffload tool
 case ${target} in
 *-intelmic-* | *-intelmicemul-*)

gcc/config/t-musl

+MULTIARCH_DIRNAME := $(subst -linux-gnu,-linux-musl,$(MULTIARCH_DIRNAME))
+MULTILIB_OSDIRNAMES := $(subst -linux-gnu,-linux-musl,$(MULTILIB_OSDIRNAMES))

gcc/config/t-uclibc

+MULTIARCH_DIRNAME := $(subst -linux-gnu,-linux-uclibc,$(MULTIARCH_DIRNAME))
+MULTILIB_OSDIRNAMES := $(subst -linux-gnu,-linux-uclibc,$(MULTILIB_OSDIRNAMES))