update gcc, stop using nosys

platformio.ini

@@ -19,6 +19,7 @@ extra_configs =
 lib_archive = no
 debug_tool = stlink
 upload_protocol = dfu
+platform_packages = toolchain-gccarmnoneeabi@~1.120301.0
 build_src_filter = +<*> -<.git/> -<.svn/> -<example/> -<examples/> -<test/> -<tests/> -<system/> -<driver/stm32> -<driver/at32>
 extra_scripts = 
   pre:script/pre_script.py
@@ -34,8 +35,7 @@ build_flags =
 
 [stm32]
 extends = common
-platform = ststm32
-platform_packages = toolchain-gccarmnoneeabi@~1.90201.0
+platform = ststm32@~17.0.0
 build_src_filter = ${common.build_src_filter} +<driver/stm32>
 framework = stm32cube
 board_build.stm32cube.custom_system_setup = yes
@@ -136,7 +136,6 @@ extends = stm32h743
 [at32]
 extends = common
 platform = https://github.com/ArteryTek/platform-arterytekat32.git#5729d36
-platform_packages = toolchain-gccarmnoneeabi@~1.90201.0
 framework = at32firmlib
 board_build.at32firmlib.custom_system_setup = yes
 build_src_filter = ${common.build_src_filter} +<driver/at32>

script/post_script.py

@@ -22,8 +22,8 @@ def before_upload(source, target, env):
             time.sleep(2)
 
 
-remove_flags = ["-lgcc", "-lstdc++"]
-for scope in ("ASFLAGS", "CCFLAGS", "LINKFLAGS"):
+remove_flags = ["gcc", "stdc++", "nosys", "--specs=nosys.specs"]
+for scope in ("ASFLAGS", "CCFLAGS", "LINKFLAGS", "LIBS"):
     for option in remove_flags:
         while option in env[scope]:
             env[scope].remove(option)

script/pre_script.py

@@ -28,7 +28,7 @@
 ]
 
 if env.GetBuildType() == "release":
-    common_flags.insert(0, "-flto")
+    common_flags.insert(0, "-flto=auto")
     common_flags.insert(0, "-Ofast")
 
 git_version = porcelain.describe(".")

src/core/syscalls.c

@@ -0,0 +1,22 @@
+#include <sys/types.h>
+
+register char *stack_ptr asm("sp");
+uint __heap_limit = 0xcafedead;
+
+__attribute__((__used__)) void *_sbrk(ptrdiff_t incr) {
+  extern char end asm("end"); /* Defined by the linker.  */
+  static char *heap_end;
+
+  if (heap_end == NULL)
+    heap_end = &end;
+
+  const char *prev_heap_end = heap_end;
+
+  if ((heap_end + incr > stack_ptr) ||
+      (__heap_limit != 0xcafedead && heap_end + incr > (char *)__heap_limit)) {
+    return (void *)-1;
+  }
+
+  heap_end += incr;
+  return (void *)prev_heap_end;
+}