[Buildroot] [git commit branch/2020.02.x] Makefile: make-4.3 now longer un-escapes \# in macros
Peter Korsgaard
peter at korsgaard.com
Wed Apr 8 11:25:28 UTC 2020
commit: https://git.buildroot.net/buildroot/commit/?id=453352c32aafe131c10dfebe4b0b89c2845c51ff
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2020.02.x
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 at ys.lc>
[yann.morin.1998 at 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 at free.fr>
(cherry picked from commit 35c5cf56d21a250f8c86443a84e0b32301a70665)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
support/misc/utils.mk | 14 ++++++++++++++
toolchain/helpers.mk | 8 ++++----
2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/support/misc/utils.mk b/support/misc/utils.mk
index b422c67d76..2f00ccfdb7 100644
--- 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 2c2a987c3e..44d0c83d1e 100644
--- 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 \
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