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

Reported-by: Dario Gjorgjevski <[email protected]>
Signed-off-by: Taylor Blau <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ttaylorr

Makefile

@@ -1552,23 +1552,23 @@ ifneq (,$(SOCKLEN_T))
 endif
 
 ifeq ($(uname_S),Darwin)
-	ifndef NO_FINK
-		ifeq ($(shell test -d /sw/lib && echo y),y)
+        ifndef NO_FINK
+                ifeq ($(shell test -d /sw/lib && echo y),y)
 			BASIC_CFLAGS += -I/sw/include
 			BASIC_LDFLAGS += -L/sw/lib
-		endif
-	endif
-	ifndef NO_DARWIN_PORTS
-		ifeq ($(shell test -d /opt/local/lib && echo y),y)
+                endif
+        endif
+        ifndef NO_DARWIN_PORTS
+                ifeq ($(shell test -d /opt/local/lib && echo y),y)
 			BASIC_CFLAGS += -I/opt/local/include
 			BASIC_LDFLAGS += -L/opt/local/lib
-		endif
-	endif
-	ifndef NO_APPLE_COMMON_CRYPTO
+                endif
+        endif
+        ifndef NO_APPLE_COMMON_CRYPTO
 		NO_OPENSSL = YesPlease
 		APPLE_COMMON_CRYPTO = YesPlease
 		COMPAT_CFLAGS += -DAPPLE_COMMON_CRYPTO
-	endif
+        endif
 	PTHREAD_LIBS =
 endif
 
@@ -1607,53 +1607,53 @@ ifdef NO_CURL
 	REMOTE_CURL_NAMES =
 	EXCLUDED_PROGRAMS += git-http-fetch git-http-push
 else
-	ifdef CURLDIR
+        ifdef CURLDIR
 		# Try "-Wl,-rpath=$(CURLDIR)/$(lib)" in such a case.
 		CURL_CFLAGS = -I$(CURLDIR)/include
 		CURL_LIBCURL = $(call libpath_template,$(CURLDIR)/$(lib))
-	else
+        else
 		CURL_CFLAGS =
 		CURL_LIBCURL =
-	endif
+        endif
 
-	ifndef CURL_LDFLAGS
+        ifndef CURL_LDFLAGS
 		CURL_LDFLAGS = $(eval CURL_LDFLAGS := $$(shell $$(CURL_CONFIG) --libs))$(CURL_LDFLAGS)
-	endif
+        endif
 	CURL_LIBCURL += $(CURL_LDFLAGS)
 
-	ifndef CURL_CFLAGS
+        ifndef CURL_CFLAGS
 		CURL_CFLAGS = $(eval CURL_CFLAGS := $$(shell $$(CURL_CONFIG) --cflags))$(CURL_CFLAGS)
-	endif
+        endif
 	BASIC_CFLAGS += $(CURL_CFLAGS)
 
 	REMOTE_CURL_PRIMARY = git-remote-http$X
 	REMOTE_CURL_ALIASES = git-remote-https$X git-remote-ftp$X git-remote-ftps$X
 	REMOTE_CURL_NAMES = $(REMOTE_CURL_PRIMARY) $(REMOTE_CURL_ALIASES)
 	PROGRAM_OBJS += http-fetch.o
 	PROGRAMS += $(REMOTE_CURL_NAMES)
-	ifndef NO_EXPAT
+        ifndef NO_EXPAT
 		PROGRAM_OBJS += http-push.o
-	endif
+        endif
 	curl_check := $(shell (echo 072200; $(CURL_CONFIG) --vernum | sed -e '/^70[BC]/s/^/0/') 2>/dev/null | sort -r | sed -ne 2p)
-	ifeq "$(curl_check)" "072200"
+        ifeq "$(curl_check)" "072200"
 		USE_CURL_FOR_IMAP_SEND = YesPlease
-	endif
-	ifdef USE_CURL_FOR_IMAP_SEND
+        endif
+        ifdef USE_CURL_FOR_IMAP_SEND
 		BASIC_CFLAGS += -DUSE_CURL_FOR_IMAP_SEND
 		IMAP_SEND_BUILDDEPS = http.o
 		IMAP_SEND_LDFLAGS += $(CURL_LIBCURL)
-	endif
-	ifndef NO_EXPAT
-		ifdef EXPATDIR
+        endif
+        ifndef NO_EXPAT
+                ifdef EXPATDIR
 			BASIC_CFLAGS += -I$(EXPATDIR)/include
 			EXPAT_LIBEXPAT = $(call libpath_template,$(EXPATDIR)/$(lib)) -lexpat
-		else
+                else
 			EXPAT_LIBEXPAT = -lexpat
-		endif
-		ifdef EXPAT_NEEDS_XMLPARSE_H
+                endif
+                ifdef EXPAT_NEEDS_XMLPARSE_H
 			BASIC_CFLAGS += -DEXPAT_NEEDS_XMLPARSE_H
-		endif
-	endif
+                endif
+        endif
 endif
 IMAP_SEND_LDFLAGS += $(OPENSSL_LINK) $(OPENSSL_LIBSSL) $(LIB_4_CRYPTO)
 
@@ -1665,15 +1665,15 @@ EXTLIBS += -lz
 
 ifndef NO_OPENSSL
 	OPENSSL_LIBSSL = -lssl
-	ifdef OPENSSLDIR
+        ifdef OPENSSLDIR
 		BASIC_CFLAGS += -I$(OPENSSLDIR)/include
 		OPENSSL_LINK = $(call libpath_template,$(OPENSSLDIR)/$(lib))
-	else
+        else
 		OPENSSL_LINK =
-	endif
-	ifdef NEEDS_CRYPTO_WITH_SSL
+        endif
+        ifdef NEEDS_CRYPTO_WITH_SSL
 		OPENSSL_LIBSSL += -lcrypto
-	endif
+        endif
 else
 	BASIC_CFLAGS += -DNO_OPENSSL
 	OPENSSL_LIBSSL =
@@ -1691,18 +1691,18 @@ ifdef APPLE_COMMON_CRYPTO
 endif
 endif
 ifndef NO_ICONV
-	ifdef NEEDS_LIBICONV
-		ifdef ICONVDIR
+        ifdef NEEDS_LIBICONV
+                ifdef ICONVDIR
 			BASIC_CFLAGS += -I$(ICONVDIR)/include
 			ICONV_LINK = $(call libpath_template,$(ICONVDIR)/$(lib))
-		else
+                else
 			ICONV_LINK =
-		endif
-		ifdef NEEDS_LIBINTL_BEFORE_LIBICONV
+                endif
+                ifdef NEEDS_LIBINTL_BEFORE_LIBICONV
 			ICONV_LINK += -lintl
-		endif
+                endif
 		EXTLIBS += $(ICONV_LINK) -liconv
-	endif
+        endif
 endif
 ifdef ICONV_OMITS_BOM
 	BASIC_CFLAGS += -DICONV_OMITS_BOM
@@ -1823,10 +1823,10 @@ ifdef NO_MMAP
 	COMPAT_CFLAGS += -DNO_MMAP
 	COMPAT_OBJS += compat/mmap.o
 else
-	ifdef USE_WIN32_MMAP
+        ifdef USE_WIN32_MMAP
 		COMPAT_CFLAGS += -DUSE_WIN32_MMAP
 		COMPAT_OBJS += compat/win32mmap.o
-	endif
+        endif
 endif
 ifdef MMAP_PREVENTS_DELETE
 	BASIC_CFLAGS += -DMMAP_PREVENTS_DELETE
@@ -1951,11 +1951,11 @@ else
 	BASIC_CFLAGS += -DSHA1_DC
 	LIB_OBJS += sha1dc_git.o
 ifdef DC_SHA1_EXTERNAL
-	ifdef DC_SHA1_SUBMODULE
-		ifneq ($(DC_SHA1_SUBMODULE),auto)
+        ifdef DC_SHA1_SUBMODULE
+                ifneq ($(DC_SHA1_SUBMODULE),auto)
 $(error Only set DC_SHA1_EXTERNAL or DC_SHA1_SUBMODULE, not both)
-		endif
-	endif
+                endif
+        endif
 	BASIC_CFLAGS += -DDC_SHA1_EXTERNAL
 	EXTLIBS += -lsha1detectcoll
 else