+ added several missing targets to the help screen for the -P compiler option

compiler/msg/errore.msg

@@ -4223,7 +4223,7 @@ L*2il_Return list of supported LLVM/Xcode versions by the LLVM backend
 F*1P<x>_Target CPU / compiler related options:
 F*2PB_Show default compiler binary
 F*2PP_Show default target cpu
-F*2P<x>_Set target CPU (aarch64,arm,avr,i386,i8086,jvm,m68k,mips,mipsel,powerpc,powerpc64,sparc,x86_64)
+F*2P<x>_Set target CPU (aarch64,arm,avr,i386,i8086,jvm,loongarch64,m68k,mips,mipsel,powerpc,powerpc64,riscv32,riscv64,sparc,sparc64,wasm32,x86_64,xtensa,z80)
 **1R<x>_Assembler reading style:
 **2Rdefault_Use default assembler for target
 3*2Ratt_Read AT&T style assembler