package/kmsxx: don't install static libraries when BR2_SHARED_STATIC_LIBS=y

The kmsxx build system can only build either shared libraries *or*
static libraries, not both. Therefore, the build currently fails when
BR2_SHARED_STATIC_LIBS=y because we try to install the static
libraries, that haven't been built.

We fix this by not installing the static libraries when
BR2_SHARED_STATIC_LIBS=y, making BR2_SHARED_STATIC_LIBS=y essentially
the same as BR2_SHARED_LIBS=y for this package.

Fixes bug #10331.

Reported-by:  Frederic MATHIEU <frederic.mathieu@dualis.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
(cherry picked from commit 28d5ca9c96f5144e86fac7ec6485fa5634cd6e97)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/kmsxx/kmsxx.mk

@@ -44,12 +44,15 @@ define KMSXX_INSTALL_TARGET_CMDS
 	$(KMSXX_INSTALL_TARGET_TESTS)
 endef
 
+# kmsxx only builds shared or static libraries, so when
+# BR2_SHARED_STATIC_LIBS=y, we don't have any static library to
+# install
 define KMSXX_INSTALL_STAGING_CMDS
 	$(foreach l,$(KMSXX_LIBS),\
 		$(if $(BR2_SHARED_LIBS)$(BR2_SHARED_STATIC_LIBS),
 			$(INSTALL) -D -m 0755 $(@D)/lib/lib$(l).so \
 				$(STAGING_DIR)/usr/lib/lib$(l).so)
-		$(if $(BR2_STATIC_LIBS)$(BR2_SHARED_STATIC_LIBS),
+		$(if $(BR2_STATIC_LIBS),
 			$(INSTALL) -D -m 0755 $(@D)/lib/lib$(l).a \
 				$(STAGING_DIR)/usr/lib/lib$(l).a)
 		mkdir -p $(STAGING_DIR)/usr/include/$(l)