toolchain: add hidden symbol for PIE support

uClibc-ng does not support PIE for some architectures as
arc and m68k. It isn't implemented in the static linking case, too.
With musl toolchains you might have static PIE support with little
patching of gcc. Static linking for GNU libc isn't enabled in
buildroot. Fixup any package using special treatment of PIE.
(grep -ir pie package/*/*.mk)

Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
[Thomas: use positive logic.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/bluez_utils/bluez_utils.mk

@@ -54,8 +54,7 @@ BLUEZ_UTILS_CONF_OPTS +=	\
 	--disable-usb
 endif
 
-# PIE is broken for m68k
-ifeq ($(BR2_m68k),y)
+ifeq ($(BR2_TOOLCHAIN_SUPPORTS_PIE),)
 BLUEZ_UTILS_CONF_OPTS += --disable-pie
 endif
 

package/cifs-utils/cifs-utils.mk

@@ -10,7 +10,7 @@ CIFS_UTILS_SITE = http://ftp.samba.org/pub/linux-cifs/cifs-utils
 CIFS_UTILS_LICENSE = GPLv3+
 CIFS_UTILS_LICENSE_FILES = COPYING
 
-ifneq ($(BR2_STATIC_LIBS)$(BR2_m68k),)
+ifeq ($(BR2_TOOLCHAIN_SUPPORTS_PIE),)
 CIFS_UTILS_CONF_OPTS += --disable-pie
 endif
 

package/libmemcached/libmemcached.mk

@@ -18,9 +18,7 @@ LIBMEMCACHED_AUTORECONF = YES
 LIBMEMCACHED_LICENSE = BSD-3c
 LIBMEMCACHED_LICENSE_FILES = COPYING
 
-# Help libmemcached to understand that -fPIE and -pie should not be
-# used when linking statically.
-ifeq ($(BR2_STATIC_LIBS),y)
+ifeq ($(BR2_TOOLCHAIN_SUPPORTS_PIE),)
 LIBMEMCACHED_CONF_ENV += \
 	ax_cv_check_cflags__Werror__fPIE=no \
 	ax_cv_check_cflags__Werror__pie=no \

package/libsodium/libsodium.mk

@@ -10,7 +10,7 @@ LIBSODIUM_LICENSE = ISC
 LIBSODIUM_LICENSE_FILES = LICENSE
 LIBSODIUM_INSTALL_STAGING = YES
 
-ifeq ($(BR2_arc),y)
+ifeq ($(BR2_TOOLCHAIN_SUPPORTS_PIE),)
 LIBSODIUM_CONF_OPTS += --disable-pie
 endif
 

package/lvm2/lvm2.mk

@@ -43,7 +43,7 @@ else
 LVM2_CONF_OPTS += --disable-applib
 endif
 
-ifeq ($(BR2_arc)$(BR2_m68k),y)
+ifeq ($(BR2_TOOLCHAIN_SUPPORTS_PIE),)
 LVM2_CONF_ENV += ac_cv_flag_HAVE_PIE=no
 endif
 

package/openssh/openssh.mk

@@ -22,12 +22,7 @@ define OPENSSH_USERS
 	sshd -1 sshd -1 * - - - SSH drop priv user
 endef
 
-# uClibc toolchain for ARC doesn't support PIE at the moment
-ifeq ($(BR2_arc),y)
-OPENSSH_CONF_OPTS += --without-pie
-endif
-# PIE and static does not work on Linux
-ifeq ($(BR2_STATIC_LIBS),y)
+ifeq ($(BR2_TOOLCHAIN_SUPPORTS_PIE),)
 OPENSSH_CONF_OPTS += --without-pie
 endif
 

package/openswan/openswan.mk

@@ -11,8 +11,8 @@ OPENSWAN_LICENSE_FILES = COPYING LICENSE
 
 OPENSWAN_DEPENDENCIES = host-bison host-flex gmp iproute2
 OPENSWAN_MAKE_OPTS = ARCH=$(BR2_ARCH) CC="$(TARGET_CC)" \
-	USERCOMPILE="$(TARGET_CFLAGS) $(if $(BR2_STATIC_LIBS),,-fPIE)" \
-	USERLINK="$(TARGET_LDFLAGS) $(if $(BR2_STATIC_LIBS),,-fPIE)" \
+	USERCOMPILE="$(TARGET_CFLAGS) $(if $(BR2_TOOLCHAIN_SUPPORTS_PIE),-fPIE)" \
+	USERLINK="$(TARGET_LDFLAGS) $(if $(BR2_TOOLCHAIN_SUPPORTS_PIE),-fPIE)" \
 	INC_USRLOCAL=/usr USE_KLIPS=false USE_MAST=false USE_NM=false
 
 ifeq ($(BR2_PACKAGE_LIBCURL),y)

package/pure-ftpd/pure-ftpd.mk

@@ -41,7 +41,7 @@ else
 PURE_FTPD_CONF_OPTS += --without-tls
 endif
 
-ifeq ($(BR2_arc),y)
+ifeq ($(BR2_TOOLCHAIN_SUPPORTS_PIE),)
 PURE_FTPD_CONF_ENV += ax_cv_check_cflags___fPIE=no ax_cv_check_ldflags___fPIE=no
 endif
 

package/quagga/quagga.mk

@@ -68,7 +68,7 @@ else
 QUAGGA_CONF_OPTS += --disable-vtysh
 endif
 
-ifeq ($(BR2_arc),y)
+ifeq ($(BR2_TOOLCHAIN_SUPPORTS_PIE),)
 QUAGGA_CONF_OPTS += --disable-pie
 endif
 

package/tinc/tinc.mk

@@ -11,7 +11,7 @@ TINC_LICENSE = GPLv2+ with OpenSSL exception
 TINC_LICENSE_FILES = COPYING COPYING.README
 TINC_CONF_ENV = CFLAGS="$(TARGET_CFLAGS) -std=c99"
 
-ifeq ($(BR2_arc),y)
+ifeq ($(BR2_TOOLCHAIN_SUPPORTS_PIE),)
 TINC_CONF_ENV += \
 	ax_cv_check_cflags___fPIE=no \
 	ax_cv_check_ldflags___pie=no

package/trousers/trousers.mk

@@ -23,8 +23,7 @@ endif
 # workaround.
 TROUSERS_CONF_OPTS += --disable-usercheck
 
-# uClibc toolchain for ARC doesn't support PIE at the moment
-ifeq ($(BR2_arc),y)
+ifeq ($(BR2_TOOLCHAIN_SUPPORTS_PIE),)
 TROUSERS_CONF_ENV += \
 	ax_cv_check_cflags___fPIE__DPIE=no \
 	ax_cv_check_ldflags___pie=no

toolchain/Config.in

@@ -15,9 +15,11 @@ config BR2_TOOLCHAIN_USES_GLIBC
 	select BR2_TOOLCHAIN_HAS_THREADS_DEBUG
 	select BR2_TOOLCHAIN_HAS_THREADS_NPTL
 	select BR2_TOOLCHAIN_HAS_SHADOW_PASSWORDS
+	select BR2_TOOLCHAIN_SUPPORTS_PIE
 
 config BR2_TOOLCHAIN_USES_UCLIBC
 	bool
+	select BR2_TOOLCHAIN_SUPPORTS_PIE if !BR2_arc && !BR2_m68k && !BR2_STATIC_LIBS
 
 config BR2_TOOLCHAIN_USES_MUSL
 	bool
@@ -26,6 +28,7 @@ config BR2_TOOLCHAIN_USES_MUSL
 	select BR2_TOOLCHAIN_HAS_THREADS
 	select BR2_TOOLCHAIN_HAS_THREADS_DEBUG
 	select BR2_TOOLCHAIN_HAS_THREADS_NPTL
+	select BR2_TOOLCHAIN_SUPPORTS_PIE
 
 choice
 	prompt "Toolchain type"

toolchain/toolchain-common.in

@@ -39,6 +39,9 @@ config BR2_TOOLCHAIN_HAS_SHADOW_PASSWORDS
 config BR2_TOOLCHAIN_HAS_SSP
 	bool
 
+config BR2_TOOLCHAIN_SUPPORTS_PIE
+	bool
+
 config BR2_ENABLE_LOCALE_PURGE
 	bool "Purge unwanted locales"
 	help