Roll gyp r1970:1972

r1972: Makes matching of build files work when absolute Matching wasn't
     working if paths supplied were absolute.
r1971: Support for custom NM/readelf binaries in your toolchain.

BUG=109173
TEST=none
R=scottmg@chromium.org

Review URL: https://codereview.chromium.org/533993002

Cr-Commit-Position: refs/heads/master@{#293041}

DEPS

@@ -157,7 +157,7 @@ deps = {
     Var('chromium_git') + '/external/grit-i18n.git' + '@' + '77abf65c1d72af6fb7f9ef6f50cdf29fcf42d0a1', # from svn revision 175
 
   'src/tools/gyp':
-    Var('chromium_git') + '/external/gyp.git' + '@' + '43a3b907eb20bd59c28c6e315b3d9e348ab57ac7', # from svn revision 1970
+    Var('chromium_git') + '/external/gyp.git' + '@' + '6760f5b1a4852fd6ccbe4ffc409d73edac445744', # from svn revision 1972
 
   'src/tools/swarming_client':
    Var('chromium_git') + '/external/swarming.client.git' + '@' +  Var('swarming_revision'),