Bug 1265627 - Remove the CXX_VERSION AC_SUBST. r=ted

Its only use is in buildconfig.html, and configure guarantees it's
always the same version as CC_VERSION, so just use that.

js/src/old-configure.in

@@ -2604,7 +2604,6 @@ AC_SUBST(BIN_SUFFIX)
 AC_SUBST(IMPORT_LIB_SUFFIX)
 AC_SUBST(USE_N32)
 AC_SUBST(CC_VERSION)
-AC_SUBST(CXX_VERSION)
 AC_SUBST(MSMANIFEST_TOOL)
 AC_SUBST(MOZ_LINKER)
 AC_SUBST(WIN32_CONSOLE_EXE_LDFLAGS)

old-configure.in

@@ -7210,7 +7210,6 @@ AC_SUBST(BIN_SUFFIX)
 AC_SUBST(IMPORT_LIB_SUFFIX)
 AC_SUBST(USE_N32)
 AC_SUBST(CC_VERSION)
-AC_SUBST(CXX_VERSION)
 AC_SUBST(MSMANIFEST_TOOL)
 AC_SUBST(NS_ENABLE_TSF)
 AC_SUBST(WIN32_CONSOLE_EXE_LDFLAGS)

toolkit/content/buildconfig.html

@@ -49,7 +49,7 @@
     </tr>
     <tr>
       <td>@CXX@</td>
-      <td>@CXX_VERSION@</td>
+      <td>@CC_VERSION@</td>
 #ifndef BUILD_FASTER
       <td>@CXXFLAGS@ @CPPFLAGS@</td>
 #endif

toolkit/content/moz.build

@@ -6,8 +6,7 @@
 
 TEST_DIRS += ['tests']
 
-for var in ('target', 'MOZ_CONFIGURE_OPTIONS', 'CC', 'CC_VERSION',
-            'CXX', 'CXX_VERSION'):
+for var in ('target', 'MOZ_CONFIGURE_OPTIONS', 'CC', 'CC_VERSION', 'CXX'):
     DEFINES[var] = CONFIG[var]
 
 DEFINES['CFLAGS'] = CONFIG['OS_CFLAGS']