tests: make chunk header of external diff glob-ed for portability Before this patch, some tests using external "diff" command via extdiff extension fail on Solaris, because system standard "diff" (= /usr/bin/diff) on Solaris always generates chunk headers below: - "@@ -1,0 +1,nnnn @@" for added file - "@@ -1,nnnn +1,0 @@" for removed file even though "diff" on Linux generates: - "@@ -0,0 +1,nnnn @@" for added file - "@@ -1,nnnn +0,0 @@" for removed file This patch makes chunk header of external diff glob-ed for portability of tests. "hg diff" output follows Linux style, and there are many such diff output lines in existing tests. This is reason why this patch doesn't add check-code.py any rule to detect such diff output in tests. This patch is a part of making tests using external "diff" portable, and test-subrepo-deep-nested-change.t isn't yet portable even after this patch.