Add RTTI menu to support apps which need RTTI (#338)

By default RTTI (Run-Time Type Information) is disabled because most apps
don't need run time type info enabled.  However, certain libraries expect
to be able to query types of objects at runtime, so add a menu to enable it.

platform.txt

@@ -52,7 +52,7 @@ compiler.c.elf.flags={compiler.warning_flags} {compiler.defines} {compiler.flags
 compiler.S.cmd=arm-none-eabi-gcc
 compiler.S.flags=-c {compiler.warning_flags} -g -x assembler-with-cpp -MMD {compiler.includes} -g
 compiler.cpp.cmd=arm-none-eabi-g++
-compiler.cpp.flags=-c {compiler.warning_flags} {compiler.defines} {compiler.flags} {compiler.includes} -fno-rtti -std=gnu++17 -g
+compiler.cpp.flags=-c {compiler.warning_flags} {compiler.defines} {compiler.flags} {compiler.includes} {build.flags.rtti} -std=gnu++17 -g
 
 compiler.ar.cmd=arm-none-eabi-ar
 compiler.ar.flags=rcs
@@ -80,7 +80,8 @@ compiler.elf2hex.extra_flags=
 # Board configuration, set in boards.txt.  Present here to ensure substitution works
 build.flash_length=
 build.eeprom_start=
-build.flags.optimize=
+build.flags.optimize=-Os
+build.flags.rtti=-fno-rtti
 build.fs_start=
 build.fs_end=
 build.usbstack_flags=

tools/makeboards.py

@@ -42,6 +42,12 @@ def BuildOptimize(name):
         print("%s.menu.opt.%s=%s (%s) %s" % (name, l[0], l[1], l[2], l[3]))
         print("%s.menu.opt.%s.build.flags.optimize=%s" % (name, l[0], l[2]))
 
+def BuildRTTI(name):
+    print("%s.menu.rtti.Disabled=Disabled" % (name))
+    print("%s.menu.rtti.Disabled.build.flags.rtti=-fno-rtti" % (name))
+    print("%s.menu.rtti.Enabled=Enabled" % (name))
+    print("%s.menu.rtti.Enabled.build.flags.rtti=" % (name))
+
 def BuildBoot(name):
     for l in [ ("Generic SPI /2", "boot2_generic_03h_2_padded_checksum"),  ("Generic SPI /4", "boot2_generic_03h_4_padded_checksum"),
             ("IS25LP080 QSPI /2", "boot2_is25lp080_2_padded_checksum"), ("IS25LP080 QSPI /4", "boot2_is25lp080_4_padded_checksum"),
@@ -97,6 +103,7 @@ def BuildGlobalMenuList():
     print("menu.flash=Flash Size")
     print("menu.freq=CPU Speed")
     print("menu.opt=Optimize")
+    print("menu.rtti=RTTI")
     print("menu.dbgport=Debug Port")
     print("menu.dbglvl=Debug Level")
     print("menu.boot2=Boot Stage 2")
@@ -130,6 +137,7 @@ def MakeBoard(name, vendor_name, product_name, vid, pid, boarddefine, flashsizem
             BuildFlashMenu(n, flashsizemb * 1024 * 1024, fssizelist)
         BuildFreq(n)
         BuildOptimize(n)
+        BuildRTTI(n)
         BuildDebugPort(n)
         BuildDebugLevel(n)
         if a == "picodebug":