Use thumb versions of external libraries with ARMv7.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index b8a87e09c707e3b6bc7cf47fcd41bbcdd8499e9a..7e4970e8f033eb615c48288267e8f00849ede1cc 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -164,6 +164,9 @@
         # Set ARM architecture version.
         'arm_version%': 7,
 
+        # Use Thumb on ARMv7
+        'arm_thumb%':0,
+
         # Use aurax11 for clipboard implementation. This is true on linux_aura.
         'use_clipboard_aurax11%': 0,
 
@@ -299,6 +302,7 @@
       'buildtype%': '<(buildtype)',
       'branding%': '<(branding)',
       'arm_version%': '<(arm_version)',
+      'arm_thumb%': '<(arm_thumb)',
       'sysroot%': '<(sysroot)',
       'chroot_cmd%': '<(chroot_cmd)',
       'system_libdir%': '<(system_libdir)',
@@ -2342,6 +2346,13 @@
       }, {
          'use_seccomp_bpf%': 0,
       }],
+
+      ['arm_thumb==1', {
+        'thumb_option%': "-mthumb",
+      }, {
+        'thumb_option%': "",
+      }],
+
       # Set component build with LTO until all tests pass.
       # This also reduces link time.
       ['use_lto==1', {
@@ -3799,6 +3810,7 @@
           ['target_arch=="arm"', {
             'target_conditions': [
               ['_toolset=="target"', {
+                'cflags': [ '<(thumb_option)' ],
                 'conditions': [
                   ['clang==0', {
                     'cflags_cc': [
@@ -3872,16 +3884,9 @@
                       }],
                     ],
                   }],
-                  ['arm_thumb==1', {
-                    'cflags': [
-                      '-mthumb',
-                    ],
-                    'conditions': [
-                      ['use_lto==1 or use_lto_o2==1', {
-                        'ldflags': [
-                          '-mthumb',
-                        ],
-                      }],
+                  ['use_lto==1 or use_lto_o2==1', {
+                    'ldflags': [
+                      '<(thumb_option)',
                     ],
                   }],
                   ['OS=="android"', {
@@ -4635,7 +4640,7 @@
                 'libraries': [
                   '-l<(android_stlport_library)',
                   # Manually link the libgcc.a that the cross compiler uses.
-                  '<!(<(android_toolchain)/*-gcc -print-libgcc-file-name)',
+                  '<!(<(android_toolchain)/*-gcc <(thumb_option) -print-libgcc-file-name)',
                   '-lc',
                   '-ldl',
                   '-lm',
@@ -4700,8 +4705,12 @@
                 'cflags': [
                   '-isystem<(android_stlport_include)',
                 ],
-                'ldflags': [
-                  '-L<(android_stlport_libs_dir)',
+                'conditions': [
+                  ['target_arch=="arm" and arm_thumb==1', {
+                    'ldflags': [ '-L<(android_stlport_libs_dir)/thumb' ]
+                  }, {
+                    'ldflags': [ '-L<(android_stlport_libs_dir)' ]
+                  }],
                 ],
               }, { # else: android_webview_build!=0
                 'aosp_build_settings': {