Bug 1428182 - 1. Support unified headers for Android builds; r=nalexander

NDK headers are grouped into a "sysroot" directory, which doesn't
contain architecture-specific bits, and a "system" directory, which
contains only the architecture-specific bits. Previously, both
directories are the same, under platforms/android-*/arch-*/. However,
with unified headers in NDK r16, the two are different, so we need to
support that in the Android build scripts.

Unified headers also rely on the build system defining the
__ANDROID_API__ macro, so we add support for that as well.

MozReview-Commit-ID: 9zBNQC3BRFl

--HG--
extra : rebase_source : 36c9d4d5625fecbbe2485668811f85f9d94372d5

build/autoconf/android.m4

@@ -8,12 +8,12 @@ AC_DEFUN([MOZ_ANDROID_NDK],
 case "$target" in
 *-android*|*-linuxandroid*)
     dnl $android_platform will be set for us by Python configure.
-    directory_include_args="-isystem $android_platform/usr/include"
+    directory_include_args="-isystem $android_system -isystem $android_sysroot/usr/include"
 
     # clang will do any number of interesting things with host tools unless we tell
     # it to use the NDK tools.
     extra_opts="-gcc-toolchain $(dirname $(dirname $TOOLCHAIN_PREFIX))"
-    CPPFLAGS="$extra_opts $CPPFLAGS"
+    CPPFLAGS="$extra_opts -D__ANDROID_API__=$android_version $CPPFLAGS"
     ASFLAGS="$extra_opts $ASFLAGS"
     LDFLAGS="$extra_opts $LDFLAGS"
 

build/moz.configure/android-ndk.configure

@@ -150,6 +150,56 @@ def android_platform(target, android_version, ndk, _):
 add_old_configure_assignment('android_platform', android_platform)
 
 
+@depends(android_platform, ndk, target, '--help')
+@checking('for android sysroot directory')
+@imports(_from='os.path', _import='isdir')
+def android_sysroot(android_platform, ndk, target, _):
+    if target.os != 'Android':
+        return
+
+    # NDK r15 has both unified and non-unified headers, but we only support
+    # non-unified for that NDK, so look for that first.
+    search_dirs = [
+        # (<if this directory exists>, <return this directory>)
+        (os.path.join(android_platform, 'usr', 'include'), android_platform),
+        (os.path.join(ndk, 'sysroot'), os.path.join(ndk, 'sysroot')),
+    ]
+
+    for test_dir, sysroot_dir in search_dirs:
+        if isdir(test_dir):
+            return sysroot_dir
+
+    die("Android sysroot directory not found in %s." %
+        str([sysroot_dir for test_dir, sysroot_dir in search_dirs]))
+
+
+add_old_configure_assignment('android_sysroot', android_sysroot)
+
+
+@depends(android_platform, ndk, target, '--help')
+@checking('for android system directory')
+@imports(_from='os.path', _import='isdir')
+def android_system(android_platform, ndk, target, _):
+    if target.os != 'Android':
+        return
+
+    # NDK r15 has both unified and non-unified headers, but we only support
+    # non-unified for that NDK, so look for that first.
+    search_dirs = [
+        os.path.join(android_platform, 'usr', 'include'),
+        os.path.join(ndk, 'sysroot', 'usr', 'include', target.toolchain),
+    ]
+
+    for system_dir in search_dirs:
+        if isdir(system_dir):
+            return system_dir
+
+    die("Android system directory not found in %s." % str(search_dirs))
+
+
+add_old_configure_assignment('android_system', android_system)
+
+
 @depends(target, host, ndk, '--with-android-toolchain', '--help')
 @checking('for the Android toolchain directory', lambda x: x or 'not found')
 @imports(_from='os.path', _import='isdir')
@@ -241,14 +291,19 @@ def stlport_cppflags(value, ndk, _):
 add_old_configure_assignment('stlport_cppflags', stlport_cppflags)
 
 
-@depends(android_platform, android_toolchain, stlport_cppflags)
-def extra_toolchain_flags(platform_dir, toolchain_dir, stlport_cppflags):
-    if not platform_dir:
+@depends(android_system, android_sysroot, android_toolchain, android_version,
+         stlport_cppflags)
+def extra_toolchain_flags(android_system, android_sysroot, toolchain_dir,
+                          android_version, stlport_cppflags):
+    if not android_sysroot:
         return []
     flags = ['-isystem',
-             os.path.join(platform_dir, 'usr', 'include'),
+             android_system,
+             '-isystem',
+             os.path.join(android_sysroot, 'usr', 'include'),
              '-gcc-toolchain',
-             toolchain_dir]
+             toolchain_dir,
+             '-D__ANDROID_API__=%d' % android_version]
     flags.extend(stlport_cppflags if stlport_cppflags else [])
     return flags