package/pkg-meson: support building both libraries

meson supports building both libraries (i.e. static and shared).
This will avoid the following build failure with flashrom and
BR2_SHARED_STATIC_LIBS raised since bump to version 1.4.0-rc2 in commit
8637884057ddc3c1aeb9f0dd285fc6fcf378c26b:

../output-1/build/flashrom-1.4.0-rc2/meson.build:18:2: ERROR: Problem encountered:
    Cannot build cli_classic with shared libflashrom. Use \'-Dclassic_cli=disabled\' to disable the cli,
    or use \'--default-library=both\' to also build the classic_cli

Fixes: 8637884057ddc3c1aeb9f0dd285fc6fcf378c26b
 - http://autobuild.buildroot.org/results/6d484857ff1674bf81986505827e54f3f1b9aaec

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/pkg-meson.mk

@@ -82,6 +82,14 @@ else
 PKG_MESON_TARGET_FC = /bin/false
 endif
 
+ifeq ($(BR2_STATIC_LIBS),y)
+PKG_MESON_DEFAULT_LIBRARY=static
+else ifeq ($(BR2_SHARED_LIBS),y)
+PKG_MESON_DEFAULT_LIBRARY=shared
+else ifeq ($(BR2_SHARED_STATIC_LIBS),y)
+PKG_MESON_DEFAULT_LIBRARY=both
+endif
+
 # Generates sed patterns for patching the cross-compilation.conf template,
 # since Flags might contain commas the arguments are passed indirectly by
 # variable name (stripped to deal with whitespaces).
@@ -152,7 +160,7 @@ define $(2)_CONFIGURE_CMDS
 	$$(MESON) setup \
 		--prefix=/usr \
 		--libdir=lib \
-		--default-library=$(if $(BR2_STATIC_LIBS),static,shared) \
+		--default-library=$(PKG_MESON_DEFAULT_LIBRARY) \
 		--buildtype=$(if $(BR2_ENABLE_RUNTIME_DEBUG),debug,release) \
 		--cross-file=$$($$(PKG)_SRCDIR)/build/cross-compilation.conf \
 		-Db_pie=false \