yaml: Depend on libyaml >= 0.2.3

libyaml before 0.2.3 expects non-const string parameters. Supporting
both variants would require either cpp magic or ignoring
"discarded-qualifiers" compiler warnings. For the sake of simplicity
just support libyaml 0.2.3 and newer.

Note that NO_YAML can be overwritten on the make command line.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Makefile

@@ -55,7 +55,11 @@ else
 	CFLAGS += $(shell $(PKG_CONFIG) --cflags valgrind)
 endif
 
-NO_YAML := $(shell $(PKG_CONFIG) --exists yaml-0.1; echo $$?)
+# libyaml before version 0.2.3 expects non-const string parameters. Supporting
+# both variants would require either cpp magic or passing
+# -Wno-error=discarded-qualifiers to the compiler. For the sake of simplicity
+# just support libyaml >= 0.2.3.
+NO_YAML := $(shell $(PKG_CONFIG) --atleast-version 0.2.3 yaml-0.1; echo $$?)
 ifeq ($(NO_YAML),1)
 	CFLAGS += -DNO_YAML
 else

meson.build

@@ -42,7 +42,7 @@ else
 endif
 
 yamltree = 'yamltree.c'
-yaml = dependency('yaml-0.1', required: get_option('yaml'), static: static_build)
+yaml = dependency('yaml-0.1', version: '>=0.2.3', required: get_option('yaml'), static: static_build)
 if not yaml.found()
   add_project_arguments('-DNO_YAML', language: 'c')
   yamltree = []

tests/run_tests.sh

@@ -32,7 +32,7 @@ if [ -n "$NO_YAML" ]; then
         no_yaml=false
     fi
 else
-    if pkg-config --exists yaml-0.1; then
+    if pkg-config --atleast-version 0.2.3 yaml-0.1; then
         no_yaml=false
     else
         no_yaml=true