Apply Alpine Linux specific differences to Gentoo ESP configuration:
- default PIE and SSP by default without additional CFLAGS (to clean up APKBUILD)
- do not enable -fstack-check by default (caused failures in programs that setup
  small stack in musl)
- enable -z relro by default
- enable -fstack-protector-strong instead of -fstack-protector-all by default

--- gcc-4.9.2/gcc/config/esp.h	2014-12-10 15:54:19.925060848 +0000
+++ gcc-4.9.2/gcc/config/esp.h	2014-12-10 15:59:16.793850060 +0000
@@ -4,7 +4,7 @@
 #ifndef GCC_ESP_H
 #define GCC_ESP_H
 
-/*	This file will add -fstack-protector-all, -fstack-check, -fPIE, -pie and -z now 
+/*	This file will add -fstack-protector-strong, -fPIE, -pie, -z relro and -z now 
 	as default if the defines and the spec allow it.
 	Added a hack for gcc-specs-* in toolchain-funcs.eclass and _filter-hardened in flag-o-matic.eclass
 	to support older hardened GCC patches and we don't need to change the code on gcc-specs-* and _filter-hardened.
@@ -16,11 +16,14 @@
 	ENABLE_CRTBEGINP add support for crtbeginP.o, build -static with -fPIE or -fpie.
 */
 #ifdef ENABLE_ESP
+
+	/* Enable by default on Alpine */
+	#define EFAULT_PIE_SSP
 	
 	/* Hack to support gcc-specs-* in toolchain-funcs.eclass and _filter-hardened in flag-o-matic.eclass  */
 	#define ESP_CC1_SPEC " %(esp_cc1_ssp) %(esp_cc1_pie) %(esp_cc1_strict_overflow)"
 	#if defined ( EFAULT_SSP ) || defined ( EFAULT_PIE_SSP )
-		#define ESP_CC1_SSP_SPEC "%{!fno-stack-protector: %{!fno-stack-protector-all: %{!fno-stack-check: }}}"
+		#define ESP_CC1_SSP_SPEC "%{!fno-stack-protector: %{!fno-stack-protector-all: }}"
 	#else
 		#define ESP_CC1_SSP_SPEC ""
 	#endif
@@ -34,20 +37,20 @@
 	/*	ESP_LINK_SPEC is added to LINK_PIE_SPEC if esp is enable
 		-z now will be added if we don't have -vanilla spec. We do a -pie incompatible check
 		Don't remove the specs in the end  */
-	#define ESP_LINK_SPEC "%(esp_link_now) %(esp_link_pie_check) "
+	#define ESP_LINK_SPEC "%(esp_link_now) %(esp_link_relro) %(esp_link_pie_check) "
 	#define ESP_LINK_NOW_SPEC "%{!nonow:-z now}"
+	#define ESP_LINK_RELRO_SPEC "%{!norelro:-z relro}"
 
 	/*	We use ESP_DRIVER_SELF_SPEC to add pie and ssp command-line options.  */
 	#define ESP_DRIVER_SELF_SPEC "%{D__KERNEL__:;:%{!nopie:%(esp_options_pie) \
 		%(esp_link_pie)} %(esp_options_ssp) }"
 	
-	/*  This will add -fstack-protector-all if we don't have -nostdlib -nodefaultlibs -fno-stack-protector -fstack-protector
+	/*  This will add -fstack-protector-strong if we don't have -nostdlib -nodefaultlibs -fno-stack-protector -fstack-protector
 		-fstack-protector-all and we have EFAULT_SSP or EFAULT_PIE_SSP defined.  */
 	#if defined ( EFAULT_SSP ) || defined ( EFAULT_PIE_SSP )
 		#define ESP_OPTIONS_SSP_SPEC \
 			"%{nostdlib|ffreestanding|fno-stack-protector|fstack-protector| \
-			fstack-protector-all|fstack-protector-strong:;:-fstack-protector-all} \
-			%{fstack-check|fstack-check=*:;: -fstack-check}"
+			fstack-protector-all|fstack-protector-strong:;:-fstack-protector-strong}"
 	#else
 		#define ESP_OPTIONS_SSP_SPEC ""
 	#endif
@@ -115,6 +118,7 @@
 		{ "esp_cc1_strict_overflow",					ESP_CC1_STRICT_OVERFLOW_SPEC },	\
 		{ "esp_link",								ESP_LINK_SPEC },				\
 		{ "esp_link_now",							ESP_LINK_NOW_SPEC },			\
+		{ "esp_link_relro",							ESP_LINK_RELRO_SPEC },			\
 		{ "esp_link_pie",							ESP_LINK_PIE_SPEC },			\
 		{ "esp_link_pie_check",						ESP_LINK_PIE_CHECK_SPEC },		\
 		{ "esp_driver_self",							ESP_DRIVER_SELF_SPEC },		\