The current check for libyaml based on pkg-config may succeed even if
yaml.h header is missing. Try to determine if header and library are
present by compiling a simple program.
This creates macros hostcc-header and hostcc-symbol in
scripts/Kbuild.include, which check whether a header file and a library
symbol are present on host system, by compiling a simple program.
Fixes: 067c650c456e ("dtc: Use pkg-config to locate libyaml")
Signed-off-by: Marek Behún <marek.behun@xxxxxx>
Cc: Pavel Modilaynen <pavel.modilaynen@xxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Cc: Michal Marek <michal.lkml@xxxxxxxxxxx>
Cc: linux-kbuild@xxxxxxxxxxxxxxx
---
scripts/Kbuild.include | 14 ++++++++++++++
scripts/dtc/Makefile | 10 ++++++----
2 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 6cabf20ce66a..33af76aa86c1 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -154,6 +154,20 @@ ld-version = $(shell $(LD) --version | $(srctree)/scripts/ld-version.sh)
# Usage: $(call ld-ifversion, -ge, 22252, y)
ld-ifversion = $(shell [ $(ld-version) $(1) $(2) ] && echo $(3) || echo $(4))
+# hostcc-header
+# Usage: $(call hostcc-header,header.h,-I/usr/include/libname)
+# third argument is optional
+hostcc-header = $(call try-run, \
+ { echo "\#include <$(1)>" ; echo "int main(){}"; } | \
+ $(HOSTCC) $(2) -x c - -o /dev/null,y,n)
+
+# hostcc-symbol
+# Usage: $(call hostcc-symbol,symbol_name,-llibname)
+# third argument is optional
+hostcc-symbol = $(call try-run, \
+ echo "void $(1)();int main(){$(1)();}" | \
+ $(HOSTCC) -x c - -o /dev/null $(2),y,n)
+
######
###
diff --git a/scripts/dtc/Makefile b/scripts/dtc/Makefile
index ef85f8b7d4a7..d04c03b0899d 100644
--- a/scripts/dtc/Makefile
+++ b/scripts/dtc/Makefile
@@ -12,15 +12,17 @@ dtc-objs += dtc-lexer.lex.o dtc-parser.tab.o
# Source files need to get at the userspace version of libfdt_env.h to compile
HOST_EXTRACFLAGS := -I $(srctree)/$(src)/libfdt
-ifeq ($(shell pkg-config --exists yaml-0.1 2>/dev/null && echo yes),)
+_yaml_libs = $(shell pkg-config --libs yaml-0.1 2>/dev/null)
+ifeq ($(call hostcc-header,yaml.h)$(call hostcc-symbol,yaml_get_version,\
+ $(_yaml_libs)),yy)
+dtc-objs += yamltree.o
+HOSTLDLIBS_dtc := $(_yaml_libs)
+else
ifneq ($(CHECK_DT_BINDING)$(CHECK_DTBS),)
$(error dtc needs libyaml for DT schema validation support. \
Install the necessary libyaml development package.)
endif
HOST_EXTRACFLAGS += -DNO_YAML
-else
-dtc-objs += yamltree.o
-HOSTLDLIBS_dtc := $(shell pkg-config yaml-0.1 --libs)
endif
# Generated files need one more search path to include headers in source tree
--
2.24.1
