Makefile(s): avoid recipe prefix in conditional statements

In GNU Make commit 07fcee35 ([SV 64815] Recipe lines cannot contain conditional statements, 2023-05-22) and following, conditional statements may no longer be preceded by a tab character (which Make refers to as the recipe prefix). There are a handful of spots in our various Makefile(s) which will break in a future release of Make containing 07fcee35. For instance, trying to compile the pre-image of this patch with the tip of make.git results in the following: $ make -v | head -1 && make GNU Make 4.4.90 config.mak.uname:842: *** missing 'endif'. Stop. The kernel addressed this issue in 82175d1f9430 (kbuild: Replace tabs with spaces when followed by conditionals, 2024-01-28). Address the issues in Git's tree by applying the same strategy. When a conditional word (ifeq, ifneq, ifdef, etc.) is preceded by one or more tab characters, replace each tab character with 8 space characters with the following: find . -type f -not -path './.git/*' -name Makefile -or -name '*.mak' | xargs perl -i -pe ' s/(\t+)(ifn?eq|ifn?def|else|endif)/" " x (length($1) * 8) . $2/ge unless /\\$/ ' The "unless /\\$/" removes any false-positives (like "\telse \" appearing within a shell script as part of a recipe). After doing so, Git compiles on newer versions of Make: $ make -v | head -1 && make GNU Make 4.4.90 GIT_VERSION = 2.44.0.414.gfac1dc44ca9 [...] $ echo $? 0 [j6t: cherry-picked from 728b9ac0c3b9] Reported-by: Dario Gjorgjevski <dario.gjorgjevski@gmail.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Johannes Sixt <j6t@kdbg.org>