Disable Altivec on host triplet powerpc-unknown-linux-gnuspe.

SPE is incompatible with AltiVec because it shares the same opcode range.

Patch from Sebastian Andrzej Siewior <bigeasy@linutronix.de> via Debian.
diff --git a/src/libFLAC/Makefile.am b/src/libFLAC/Makefile.am
index 636d4ab..2deb958 100644
--- a/src/libFLAC/Makefile.am
+++ b/src/libFLAC/Makefile.am
@@ -40,8 +40,13 @@
 CPUCFLAGS = -faltivec -force_cpusubtype_ALL -DFLAC__NO_ASM
 else
 # Linux-gcc for PPC does not have -force_cpusubtype_ALL, it is Darwin-specific
+CPUCFLAGS =
+if FLaC__CPU_PPC_SPE
+else
+CPUCFLAGS += -maltivec -mabi=altivec
+endif
 #@@@ PPC optimizations temporarily disabled
-CPUCFLAGS = -maltivec -mabi=altivec -DFLAC__NO_ASM
+CPUCFLAGS += -DFLAC__NO_ASM
 endif
 endif
 
@@ -58,6 +63,8 @@
 if FLaC__CPU_PPC
 ARCH_SUBDIRS = ppc
 if FLaC__HAS_AS__TEMPORARILY_DISABLED
+if FLaC__CPU_PPC_SPE
+else
 LOCAL_EXTRA_LIBADD = ppc/as/libFLAC-asm.la
 LOCAL_EXTRA_LDFLAGS = "-Wl,-read_only_relocs,warning"
 else
@@ -68,6 +75,7 @@
 endif
 endif
 endif
+endif
 
 libFLAC_la_LIBADD = $(LOCAL_EXTRA_LIBADD) @OGG_LIBS@