build: aix add conditonal flags for clang builds

Some gcc flags dont work on clang:

-mfprnd
-mno-popcntb
-fno-extern-tls-init

So now we conditionally add them when clang is not enabled

Also for clang builds we need to pass some additonal flags:

-fno-integrated-as
-fno-xl-pragma-pack

These flags are discuessed in:
https://chromium-review.googlesource.com/c/chromium/src/+/7120638

PR-URL: #62656
Reviewed-By: Richard Lau <richard.lau@ibm.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

Author: abmusse

common.gypi

@@ -591,6 +591,18 @@
           '-maix64',
         ],
         'conditions': [
+          [ 'clang==1', {
+            'cflags': [
+              '-fno-integrated-as',
+              '-fno-xl-pragma-pack',
+              '-mcpu=power9',
+            ],
+            'cflags_cc': [
+              '-fno-integrated-as',
+              '-fno-xl-pragma-pack',
+              '-mcpu=power9',
+            ],
+          }],
           [ '"<(aix_variant_name)"=="OS400"', {            # a.k.a. `IBM i`
             'ldflags': [
               '-Wl,-blibpath:/QOpenSys/pkgs/lib:/QOpenSys/usr/lib',

tools/v8_gypfiles/toolchain.gypi

@@ -330,11 +330,20 @@
         'conditions': [
           ['OS=="aix" or OS=="os400"', {
             # Work around AIX ceil, trunc and round oddities.
-            'cflags': [ '-mcpu=power9 -mfprnd' ],
+            'cflags': [ '-mcpu=power9' ],
+            'conditions': [
+              ['clang==0', {
+                'cflags': [ '-mfprnd' ],
+              }],
+            ],
           }],
           ['OS=="aix" or OS=="os400"', {
-            # Work around AIX assembler popcntb bug.
-            'cflags': [ '-mno-popcntb' ],
+            'conditions': [
+              ['clang==0', {
+                # Work around AIX assembler popcntb bug.
+                'cflags': [ '-mno-popcntb' ],
+              }],
+            ],
           }],
         ],
       }],  # ppc64
@@ -593,8 +602,13 @@
           '_ALL_SOURCE=1'],
         'conditions': [
           [ 'v8_target_arch=="ppc64"', {
-            'cflags': [ '-maix64', '-fdollars-in-identifiers', '-fno-extern-tls-init' ],
+            'cflags': [ '-maix64', '-fdollars-in-identifiers' ],
             'ldflags': [ '-maix64 -Wl,-bbigtoc' ],
+            'conditions': [
+              ['clang==0', {
+                'cflags': [ '-fno-extern-tls-init' ],
+              }],
+            ],
           }],
         ],
       }],