Don't override FORTIFY_SOURCE when building Foundation

Overriding FORTIFY_SOURCE with lcl_maybe_fortify may cause clang module
conflicts with consumers that do not override it identically.

Not disabling FORTIFY_SOURCE should have minimal performance impact. [1]

[1] https://zatoichi-engineer.github.io/2017/10/06/fortify-source.html

Author: lhoward

recipes-devtools/swift/swift-foundation-essentials.bb

@@ -33,8 +33,6 @@ EXTRA_OECMAKE += "-D_SwiftCollections_SourceDIR=${WORKDIR}/swift-collections"
 EXTRA_OECMAKE += "-DSwiftFoundation_MODULE_TRIPLE=${SWIFT_TARGET_NAME}"
 EXTRA_OECMAKE += "-DSwiftSyntax_DIR=${WORKDIR}/swift-syntax/cmake/modules"
 
-lcl_maybe_fortify="-D_FORTIFY_SOURCE=0"
-
 # Ensure the right CPU is targeted
 cmake_do_generate_toolchain_file:append() {
     sed -i 's/set([ ]*CMAKE_SYSTEM_PROCESSOR .*[ ]*)/set(CMAKE_SYSTEM_PROCESSOR ${TARGET_CPU_NAME})/' ${WORKDIR}/toolchain.cmake

recipes-devtools/swift/swift-foundation-icu.bb

@@ -23,8 +23,6 @@ TARGET_LDFLAGS += "-L${STAGING_DIR_TARGET}/usr/lib/swift/linux"
 EXTRA_OECMAKE += "-DENABLE_SWIFT=YES"
 EXTRA_OECMAKE += "-DBUILD_SHARED_LIBS=YES"
 
-lcl_maybe_fortify="-D_FORTIFY_SOURCE=0"
-
 # Ensure the right CPU is targeted
 cmake_do_generate_toolchain_file:append() {
     sed -i 's/set([ ]*CMAKE_SYSTEM_PROCESSOR .*[ ]*)/set(CMAKE_SYSTEM_PROCESSOR ${TARGET_CPU_NAME})/' ${WORKDIR}/toolchain.cmake

recipes-devtools/swift/swift-foundation.bb

@@ -43,8 +43,6 @@ EXTRA_OECMAKE += "-DENABLE_TESTING=0"
 EXTRA_OECMAKE += "-DBUILD_SHARED_LIBS=YES"
 EXTRA_OECMAKE += "-DDISPATCH_INCLUDE_PATH=${STAGING_DIR_TARGET}/${includedir}"
 
-lcl_maybe_fortify="-D_FORTIFY_SOURCE=0"
-
 # Ensure the right CPU is targeted
 cmake_do_generate_toolchain_file:append() {
     sed -i 's/set([ ]*CMAKE_SYSTEM_PROCESSOR .*[ ]*)/set(CMAKE_SYSTEM_PROCESSOR ${TARGET_CPU_NAME})/' ${WORKDIR}/toolchain.cmake