Add support for musl on ppc32

Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>

diff -Nur gcc-5.4.0.orig/gcc/config/rs6000/sysv4.h gcc-5.4.0/gcc/config/rs6000/sysv4.h
--- gcc-5.4.0.orig/gcc/config/rs6000/sysv4.h	2015-09-24 15:46:45.000000000 +0200
+++ gcc-5.4.0/gcc/config/rs6000/sysv4.h	2016-11-27 13:12:33.226953738 +0100
@@ -537,6 +537,9 @@
 #ifndef CC1_SECURE_PLT_DEFAULT_SPEC
 #define CC1_SECURE_PLT_DEFAULT_SPEC ""
 #endif
+#ifndef LINK_SECURE_PLT_DEFAULT_SPEC
+#define LINK_SECURE_PLT_DEFAULT_SPEC ""
+#endif
 
 /* Pass -G xxx to the compiler.  */
 #undef CC1_SPEC
@@ -757,17 +760,23 @@
 
 #define LINK_START_LINUX_SPEC ""
 
+#define MUSL_DYNAMIC_LINKER_E ENDIAN_SELECT("","le","")
+
 #define GLIBC_DYNAMIC_LINKER "/lib/ld.so.1"
 #define UCLIBC_DYNAMIC_LINKER "/lib/ld-uClibc.so.0"
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-powerpc" MUSL_DYNAMIC_LINKER_E "%{msoft-float:-sf}.so.1"
 #if DEFAULT_LIBC == LIBC_UCLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{mglibc:" G ";:" U "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{mglibc:" G ";:%{mmusl:" M ";:" U "}}"
+#elif DEFAULT_LIBC == LIBC_MUSL
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{mglibc:" G ";:%{muclibc:" U ";:" M "}}"
 #elif !defined (DEFAULT_LIBC) || DEFAULT_LIBC == LIBC_GLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{muclibc:" U ";:" G "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{muclibc:" U ";:%{mmusl:" M ";:" G "}}"
 #else
 #error "Unsupported DEFAULT_LIBC"
 #endif
 #define GNU_USER_DYNAMIC_LINKER \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER, MUSL_DYNAMIC_LINKER)
 
 #define LINK_OS_LINUX_SPEC "-m elf32ppclinux %{!shared: %{!static: \
   %{rdynamic:-export-dynamic} \
@@ -889,6 +898,7 @@
   { "link_os_openbsd",		LINK_OS_OPENBSD_SPEC },			\
   { "link_os_default",		LINK_OS_DEFAULT_SPEC },			\
   { "cc1_secure_plt_default",	CC1_SECURE_PLT_DEFAULT_SPEC },		\
+  { "link_secure_plt_default",	LINK_SECURE_PLT_DEFAULT_SPEC },		\
   { "cpp_os_ads",		CPP_OS_ADS_SPEC },			\
   { "cpp_os_yellowknife",	CPP_OS_YELLOWKNIFE_SPEC },		\
   { "cpp_os_mvme",		CPP_OS_MVME_SPEC },			\
diff -Nur gcc-5.4.0.orig/gcc/config/rs6000/sysv4le.h gcc-5.4.0/gcc/config/rs6000/sysv4le.h
--- gcc-5.4.0.orig/gcc/config/rs6000/sysv4le.h	2015-09-24 15:46:45.000000000 +0200
+++ gcc-5.4.0/gcc/config/rs6000/sysv4le.h	2016-11-27 13:12:33.226953738 +0100
@@ -31,3 +31,5 @@
 /* Little-endian PowerPC64 Linux uses the ELF v2 ABI by default.  */
 #define LINUX64_DEFAULT_ABI_ELFv2
 
+#undef MUSL_DYNAMIC_LINKER_E
+#define MUSL_DYNAMIC_LINKER_E ENDIAN_SELECT("","le","le")
diff -Nur gcc-5.4.0.orig/gcc/config.gcc gcc-5.4.0/gcc/config.gcc
--- gcc-5.4.0.orig/gcc/config.gcc	2015-09-10 16:17:53.000000000 +0200
+++ gcc-5.4.0/gcc/config.gcc	2016-11-27 13:14:17.149638148 +0100
@@ -2413,6 +2413,10 @@
 	    powerpc*-*-linux*paired*)
 		tm_file="${tm_file} rs6000/750cl.h" ;;
 	esac
+	case ${target} in
+	    powerpc*-*-linux*-musl*)
+		enable_secureplt=yes ;;
+	esac
 	if test x${enable_secureplt} = xyes; then
 		tm_file="rs6000/secureplt.h ${tm_file}"
 	fi