ppc: add configure check for older compilers erroring on 'd' constraint

configure

@@ -646,6 +646,15 @@ if test "$ARCH" = "powerpc" ; then
 trycppif "__NO_FPRS__ && !_SOFT_FLOAT" "$t" && fail \
   "$0: error: compiler's floating point configuration is unsupported"
 trycppif _SOFT_FLOAT "$t" && SUBARCH=${SUBARCH}-sf
+printf "checking whether compiler can use 'd' constraint in asm... "
+echo 'double f(double x) { __asm__ ("fabs %0, %1" : "=d"(x) : "d"(x)); return x; }' > "$tmpc"
+if $CC $CFLAGS_C99FSE $CPPFLAGS $CFLAGS -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
+printf "yes\n"
+else
+printf "no\n"
+CFLAGS_AUTO="$CFLAGS_AUTO -DBROKEN_PPC_D_ASM"
+CFLAGS_AUTO="${CFLAGS_AUTO# }"
+fi
 fi
 
 test "$ARCH" = "microblaze" && trycppif __MICROBLAZEEL__ "$t" \

src/math/powerpc/fabs.c

@@ -1,6 +1,6 @@
 #include <math.h>
 
-#ifdef _SOFT_FLOAT
+#if defined(_SOFT_FLOAT) || defined(BROKEN_PPC_D_ASM)
 
 #include "../fabs.c"
 

src/math/powerpc/fma.c

@@ -1,6 +1,6 @@
 #include <math.h>
 
-#ifdef _SOFT_FLOAT
+#if defined(_SOFT_FLOAT) || defined(BROKEN_PPC_D_ASM)
 
 #include "../fma.c"