Disable linker warning (earlephilhower#1114)

In arm-gnu-toolchain-12.2 we see this warning, that's not relevant to
pico. Disable it.

warning: blink.elf has a LOAD segment with RWX permissions

Fixes earlephilhower#1029

Author: peterharperuk

src/rp2_common/pico_standard_link/CMakeLists.txt

@@ -94,4 +94,20 @@ if (NOT TARGET pico_standard_link)
         target_compile_options(pico_standard_link INTERFACE -ffunction-sections -fdata-sections)
         target_link_options(pico_standard_link INTERFACE "LINKER:--gc-sections")
     endif()
+
+    # Ignore warnings about rwx segments introduced in binutils 2.39
+    execute_process(COMMAND ${CMAKE_C_COMPILER} -print-prog-name=ld RESULT_VARIABLE RUN_C_RESULT OUTPUT_VARIABLE FULL_LD_PATH
+        OUTPUT_STRIP_TRAILING_WHITESPACE)
+    if (${RUN_C_RESULT} EQUAL 0)
+        execute_process(COMMAND ${FULL_LD_PATH} --help RESULT_VARIABLE RUN_LD_RESULT OUTPUT_VARIABLE LD_HELP_OUTPUT
+            OUTPUT_STRIP_TRAILING_WHITESPACE)
+        if (${RUN_LD_RESULT} EQUAL 0)
+                set(RWX_WARNING "no-warn-rwx-segments")
+                string(FIND "${LD_HELP_OUTPUT}" "${RWX_WARNING}" LD_RWX_WARNING_SUPPORTED)
+                if (${LD_RWX_WARNING_SUPPORTED} GREATER -1)
+                    target_link_options(pico_standard_link INTERFACE "LINKER:--${RWX_WARNING}")
+                endif()
+        endif()
+    endif()
+
 endif()