ensure the avr example keeps compiling (#17663)

* ensure the avr example keeps compiling

* Update tests/avr/thello.nim

* now compiles properly

lib/system/embedded.nim

@@ -34,6 +34,10 @@ proc quitOrDebug() {.noreturn, importc: "abort", header: "<stdlib.h>", nodecl.}
 proc raiseException(e: ref Exception, ename: cstring) {.compilerRtl.} =
   sysFatal(ReraiseDefect, "exception handling is not available")
 
+proc raiseExceptionEx(e: sink(ref Exception), ename, procname, filename: cstring,
+                      line: int) {.compilerRtl.} =
+  sysFatal(ReraiseDefect, "exception handling is not available")
+
 proc reraiseException() {.compilerRtl.} =
   sysFatal(ReraiseDefect, "no exception to reraise")
 

tests/avr/nim.cfg

@@ -0,0 +1,12 @@
+avr.standalone.gcc.path = "/usr/bin"
+avr.standalone.gcc.exe = "avr-gcc"
+avr.standalone.gcc.linkerexe = "avr-gcc"
+passC = "-Os"
+passC = "-DF_CPU=16000000UL"
+passC = "-mmcu=atmega328p"
+passL = "-mmcu=atmega328p"
+passC = "-flto"
+passL = "-flto"
+cpu = "avr"
+deadCodeElim = "on"
+gc = "arc"

tests/avr/panicoverride.nim

@@ -0,0 +1,13 @@
+proc printf(frmt: cstring) {.varargs, importc, header: "<stdio.h>", cdecl.}
+proc exit(code: int) {.importc, header: "<stdlib.h>", cdecl.}
+
+{.push stack_trace: off, profiler:off.}
+
+proc rawoutput(s: string) =
+  printf("%s\n", s)
+
+proc panic(s: string) =
+  rawoutput(s)
+  exit(1)
+
+{.pop.}

tests/avr/thello.nim

@@ -0,0 +1,6 @@
+discard """
+  cmd: "nim c --compileOnly --os:standalone --exceptions:quirky -d:noSignalHandler -d:danger $file"
+  action: "compile"
+"""
+
+echo "hi"