[Buildroot] [PATCH 1/4] package/meson: fix empty arguments in cross-compilation.conf
Yann E. MORIN
yann.morin.1998 at free.fr
Mon Jun 24 20:25:47 UTC 2019
When TARGET_CFLAGS (or _LDFLAGS or _CXXFLAGS) are empty, but were
constructed by appending other variables, like:
TARGET_CFLAGS = $(SOMETHING) $(SOMETHING_ELSE)
and both variables are empty, then $(TARGET_CFLAGS) is _not_ the
null-string; it's value is a string made of a single space.
This means that the construct:
$(if $(TARGET_CFLAGS),true,false)
will in fact return 'true'.
In our case, it means that we will call:
`printf '"%s", ' `
which expands to just:
"",
which we are then happy to insert as-is in the generated
cross-compilation.conf.
Then meson, will happily call the compiler with an empty argument.
The compiler is less happy, though:
arm-none-linux-gnueabi-gcc: error: : No such file or directory
And this is not even trivial to debug either... The only clue being that
there seems to be something missing between ': :'
We fix that testing the $(strip)ed value. We can still pass the
non-$(strip) expansion, because the shell will just do it for us, and we
are then sure there is at least one non-blank word in there.
Thanks a lot to Adam for his invaluable help debugging this!
Signed-off-by: Yann E. MORIN <yann.morin.1998 at free.fr>
Cc: Adam Duskett <aduskett at gmail.com>
Cc: Eric Le Bihan <eric.le.bihan.dev at free.fr>
Cc: Arnout Vandecappelle <arnout at mind.be>
Cc: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
---
package/meson/meson.mk | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/package/meson/meson.mk b/package/meson/meson.mk
index 5b5100cccc..511be05a46 100644
--- a/package/meson/meson.mk
+++ b/package/meson/meson.mk
@@ -45,9 +45,9 @@ else
HOST_MESON_TARGET_CPU_FAMILY = $(ARCH)
endif
-HOST_MESON_SED_CFLAGS = $(if $(TARGET_CFLAGS),`printf '"%s"$(comma) ' $(TARGET_CFLAGS)`)
-HOST_MESON_SED_LDFLAGS = $(if $(TARGET_LDFLAGS),`printf '"%s"$(comma) ' $(TARGET_LDFLAGS)`)
-HOST_MESON_SED_CXXFLAGS = $(if $(TARGET_CXXFLAGS),`printf '"%s"$(comma) ' $(TARGET_CXXFLAGS)`)
+HOST_MESON_SED_CFLAGS = $(if $(strip $(TARGET_CFLAGS)),`printf '"%s"$(comma) ' $(TARGET_CFLAGS)`)
+HOST_MESON_SED_LDFLAGS = $(if $(strip $(TARGET_LDFLAGS)),`printf '"%s"$(comma) ' $(TARGET_LDFLAGS)`)
+HOST_MESON_SED_CXXFLAGS = $(if $(strip $(TARGET_CXXFLAGS)),`printf '"%s"$(comma) ' $(TARGET_CXXFLAGS)`)
# Generate a Meson cross-compilation.conf suitable for use with the
# SDK
--
2.20.1
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