Simple changes to support builds for ppc64[le] consistent with X86

These simple changes are required to allow builds on ppc64[le] systems
consistent with X86. The Makefile now recognizes both ppc64 and ppc64le, and
in the absence of PORTABLE=1, the code will be built analogously to the X86
-march=native.

Note that although GCC supports -mcpu=native -mtune=native on POWER, it
doesn't work correctly on all systems. This is why we need to get the actual
machine model from the AUX vector.

INSTALL.md

@@ -21,7 +21,7 @@ depend on gflags. You will need to have gflags installed to run `make all`. This
 use binaries compiled by `make all` in production.
 
 * By default the binary we produce is optimized for the platform you're compiling on
-(-march=native). If you want to build a portable binary, add 'PORTABLE=1' before
+(-march=native or the equivalent). If you want to build a portable binary, add 'PORTABLE=1' before
 your make commands, like this: `PORTABLE=1 make static_lib`
 
 ## Dependencies

Makefile

@@ -84,7 +84,7 @@ endif
 # compile with -O2 if debug level is not 2
 ifneq ($(DEBUG_LEVEL), 2)
 OPT += -O2 -fno-omit-frame-pointer
-ifneq ($(MACHINE),ppc64) # ppc64 doesn't support -momit-leaf-frame-pointer
+ifeq (,$(findstring ppc64,$(MACHINE))) # ppc64[le] doesn't support -momit-leaf-frame-pointer
 OPT += -momit-leaf-frame-pointer
 endif
 endif

build_tools/build_detect_platform

@@ -359,8 +359,14 @@ if test "$USE_SSE"; then
   # if Intel SSE instruction set is supported, set USE_SSE=1
   COMMON_FLAGS="$COMMON_FLAGS -msse -msse4.2 "
 elif test -z "$PORTABLE"; then
+  if test -n "`echo $TARGET_ARCHITECTURE | grep ^ppc64`"; then
+    # Tune for this POWER processor, treating '+' models as base models
+    POWER=`LD_SHOW_AUXV=1 /bin/true | grep AT_PLATFORM | grep -E -o power[0-9]+`
+    COMMON_FLAGS="$COMMON_FLAGS -mcpu=$POWER -mtune=$POWER "
+  else
     COMMON_FLAGS="$COMMON_FLAGS -march=native "
   fi
+fi
 
 PLATFORM_CCFLAGS="$PLATFORM_CCFLAGS $COMMON_FLAGS"
 PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS $COMMON_FLAGS"