configure: Group toolchain options together in help output

configure

@@ -212,7 +212,10 @@ External library support:
   --enable-x11grab         enable X11 grabbing [no]
   --enable-zlib            enable zlib [autodetect]
 
-Advanced options (experts only):
+Toolchain options:
+  --arch=ARCH              select architecture [$arch]
+  --cpu=CPU                select the minimum required CPU (affects
+                           instruction selection, may crash on older CPUs)
   --cross-prefix=PREFIX    use PREFIX for compilation tools [$cross_prefix]
   --enable-cross-compile   assume a cross-compiler is used
   --sysroot=PATH           root of cross-build tree
@@ -244,20 +247,19 @@ Advanced options (experts only):
   --extra-version=STRING   version string suffix []
   --optflags=OPTFLAGS      override optimization-related compiler flags
   --build-suffix=SUFFIX    library name suffix []
-  --malloc-prefix=PREFIX   prefix malloc and related names with PREFIX
-  --arch=ARCH              select architecture [$arch]
-  --cpu=CPU                select the minimum required CPU (affects
-                           instruction selection, may crash on older CPUs)
   --enable-pic             build position-independent code
-  --enable-sram            allow use of on-chip SRAM
   --enable-thumb           compile for Thumb instruction set
+  --enable-lto             use link-time optimization
+
+Advanced options (experts only):
+  --malloc-prefix=PREFIX   prefix malloc and related names with PREFIX
   --disable-symver         disable symbol versioning
   --enable-hardcoded-tables use hardcoded tables instead of runtime generation
   --disable-safe-bitstream-reader
                            disable buffer boundary checking in bitreaders
                            (faster, but may crash)
   --enable-memalign-hack   emulate memalign, interferes with memory debuggers
-  --enable-lto             use link-time optimization
+  --enable-sram            allow use of on-chip SRAM
 
 Optimization options (experts only):
   --disable-asm            disable all assembler optimizations