import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

build/autoconf/mozheader.m4

@@ -0,0 +1,32 @@
+dnl This Source Code Form is subject to the terms of the Mozilla Public
+dnl License, v. 2.0. If a copy of the MPL was not distributed with this
+dnl file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+dnl MOZ_CHECK_HEADER(HEADER-FILE, [ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND [, INCLUDES]]])
+AC_DEFUN([MOZ_CHECK_HEADER],
+[ dnl Do the transliteration at runtime so arg 1 can be a shell variable.
+  ac_safe=`echo "$1" | sed 'y%./+-%__p_%'`
+  AC_MSG_CHECKING([for $1])
+  AC_CACHE_VAL(ac_cv_header_$ac_safe,
+ [ AC_TRY_COMPILE([$4
+#include <$1>], ,
+                  eval "ac_cv_header_$ac_safe=yes",
+                  eval "ac_cv_header_$ac_safe=no") ])
+  if eval "test \"`echo '$ac_cv_header_'$ac_safe`\" = yes"; then
+    AC_MSG_RESULT(yes)
+    ifelse([$2], , :, [$2])
+  else
+    AC_MSG_RESULT(no)
+    ifelse([$3], , , [$3])
+  fi
+])
+
+dnl MOZ_CHECK_HEADERS(HEADER-FILE... [, ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND [, INCLUDES]]])
+AC_DEFUN([MOZ_CHECK_HEADERS],
+[ for ac_hdr in $1
+  do
+    MOZ_CHECK_HEADER($ac_hdr,
+                     [ ac_tr_hdr=HAVE_`echo $ac_hdr | sed 'y%abcdefghijklmnopqrstuvwxyz./-%ABCDEFGHIJKLMNOPQRSTUVWXYZ___%'`
+                       AC_DEFINE_UNQUOTED($ac_tr_hdr) $2], $3, [$4])
+  done
+])