Makefile: make-4.3 now longer un-escapes \# in macros

make-4.3 shipped with a backward incompatible change in how sharp signs
are handled in macros. Previously, up to make 4.2, the sharp sign would
always start a comment, unless backslash-escaped, even in a macro or a
fucntion call.

Now, the sharp sign is no longer starting a comment when it appears
inside such a macro or function call. This behaviour was supposed to be
in force since 3.81, but was not; 4.3 fixed the code to match the doc.

As such, use of external toolchains is broken, as we use the sharp sign
in the copy_toolchain_sysroot macro, in shell variable expansion to
strip off any leading /: ${target\#/}.

Fix that by applying the workaround suggested in the release annoucement
[0], by using a variable to hold a sharp sign.

[0] https://lists.gnu.org/archive/html/info-gnu/2020-01/msg00004.html

Signed-off-by: Yaroslav Syrytsia <me@ys.lc>
[yann.morin.1998@free.fr:
  - move the SHARP_SIGN definition out of Makefile and into support/
  - expand the commit log
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

diff --git a/support/misc/utils.mk b/support/misc/utils.mk
index b422c67d76b0c5f649ee590b93d4dfa797a9a4e0..2f00ccfdb79789a1978732f8bc7661c3d306a6a4 100644 (file)
--- a/support/misc/utils.mk
+++ b/support/misc/utils.mk
@@ -14,6 +14,20 @@ comma := ,
 empty :=
 space := $(empty) $(empty)
 
+# make 4.3:
+# https://lwn.net/Articles/810071/
+# Number signs (#) appearing inside a macro reference or function invocation
+#   no longer introduce comments and should not be escaped with backslashes:
+#   thus a call such as:
+#     foo := $(shell echo '#')
+#   is legal.  Previously the number sign needed to be escaped, for example:
+#     foo := $(shell echo '\#')
+#   Now this latter will resolve to "\#".  If you want to write makefiles
+#   portable to both versions, assign the number sign to a variable:
+#     H := \#
+#     foo := $(shell echo '$H')
+SHARP_SIGN := \#
+
 # Case conversion macros. This is inspired by the 'up' macro from gmsl
 # (http://gmsl.sf.net). It is optimised very heavily because these macros
 # are used a lot. It is about 5 times faster than forking a shell and tr.

diff --git a/toolchain/helpers.mk b/toolchain/helpers.mk
index 2c2a987c3eeefc2d514ff53f199794783e633093..44d0c83d1e79f00f13f05ff38ed5138fa1f4f3e9 100644 (file)
--- a/toolchain/helpers.mk
+++ b/toolchain/helpers.mk
@@ -119,12 +119,12 @@ copy_toolchain_sysroot = \
        done ; \
        for link in $$(find $(STAGING_DIR) -type l); do \
                target=$$(readlink $${link}) ; \
-               if [ "$${target}" == "$${target\#/}" ] ; then \
+               if [ "$${target}" == "$${target$(SHARP_SIGN)/}" ] ; then \
                        continue ; \
                fi ; \
-               relpath="$(call relpath_prefix,$${target\#/})" ; \
-               echo "Fixing symlink $${link} from $${target} to $${relpath}$${target\#/}" ; \
-               ln -sf $${relpath}$${target\#/} $${link} ; \
+               relpath="$(call relpath_prefix,$${target$(SHARP_SIGN)/})" ; \
+               echo "Fixing symlink $${link} from $${target} to $${relpath}$${target$(SHARP_SIGN)/}" ; \
+               ln -sf $${relpath}$${target$(SHARP_SIGN)/} $${link} ; \
        done ; \
        relpath="$(call relpath_prefix,$${ARCH_LIB_DIR})" ; \
        if [ "$${relpath}" != "" ]; then \