package/php: add libucontext optional dependency

Select libucontext if the toolchain doesn't support ucontext to allow
building php on musl

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit 2824aa8a23a765b660219c129d4980f1b7c7691c)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/php/Config.in

@@ -9,6 +9,7 @@ config BR2_PACKAGE_PHP_ARCH_SUPPORTS
 	default y if BR2_RISCV_64
 	default y if BR2_s390x
 	default y if BR2_TOOLCHAIN_HAS_UCONTEXT
+	default y if BR2_PACKAGE_LIBUCONTEXT_ARCH_SUPPORTS
 
 config BR2_PACKAGE_PHP
 	bool "php"
@@ -25,6 +26,8 @@ config BR2_PACKAGE_PHP
 	       BR2_USE_MMU
 	select BR2_PACKAGE_PHP_SAPI_CLI if !BR2_USE_MMU
 	select BR2_PACKAGE_PCRE2
+	select BR2_PACKAGE_LIBUCONTEXT if \
+		BR2_PACKAGE_LIBUCONTEXT_ARCH_SUPPORTS
 	help
 	  PHP  is a widely-used general-purpose scripting
 	  language that is especially suited for Web development

package/php/php.mk

@@ -40,6 +40,11 @@ ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
 PHP_EXTRA_LIBS += -latomic
 endif
 
+ifeq ($(BR2_PACKAGE_LIBUCONTEXT),y)
+PHP_DEPENDENCIES += libucontext
+PHP_EXTRA_LIBS += -lucontext
+endif
+
 ifeq ($(call qstrip,$(BR2_TARGET_LOCALTIME)),)
 PHP_LOCALTIME = UTC
 else