Nim stopped working on my Mac M1 : string.h missing (problem with homebrew or Xtools)?

[Serge]

Hi,

I am using a Mac M1 (silicon), I have Xtools installed.

It runs Mac OSX Monterey

I had installed Nim with brew

"arch -arm64 brew install nim"

And it worked OK until now.

Nim does not work any more today, however: I get error messages of the kind:
    
    
    Error: execution of an external compiler program 'clang -c  -w 
-ferror-limit=3   -I/opt/homebrew/Cellar/nim/1.6.0/nim/lib 
-I/Users/sergehulne/Documents/code/Nim/tst_1 -o 
/Users/sergehulne/.cache/nim/main_d/stdlib_io.nim.c.o 
/Users/sergehulne/.cache/nim/main_d/stdlib_io.nim.c' failed with exit code: 1
    
    
    1 error generated.
    /Users/sergehulne/.cache/nim/main_d/stdlib_parseutils.nim.c:9:10: fatal 
error: 'math.h' file not found
    #include <math.h>
             ^~~~~~~~
    sergehulne@Serges-Mac-mini tst_1 % 1 error generated.
    /Users/sergehulne/.cache/nim/main_d/stdlib_unicode.nim.c:9:10: fatal error: 
'math.h' file not found
    #include <math.h>
             ^~~~~~~~
    /Users/sergehulne/.cache/nim/main_d/@mmain.nim.c:9:10: fatal error: 
'string.h' file not found
    #include <string.h>
             ^~~~~~~~~~
    /Users/sergehulne/.cache/nim/main_d/stdlib_strformat.nim.c:9:10: fatal 
error: 'string.h' file not found
    
    
    Run

and similar, if I try to reinstall Nim from source: when attempting to run 
build.h, I get
    
    
    sergehulne@Serges-Mac-mini csources % sh build.sh
    # OS: macosx
    # CPU: amd64
    clang -w -O3 -fno-strict-aliasing -Ic_code -c 
c_code/1_2/stdlib_assertions.nim.c -o c_code/1_2/stdlib_assertions.nim.o
    clang -w -O3 -fno-strict-aliasing -Ic_code -c 
c_code/1_2/stdlib_dollars.nim.c -o c_code/1_2/stdlib_dollars.nim.o
    c_code/1_2/stdlib_dollars.nim.c:7:10: fatal error: 'string.h' file not found
    #include <string.h>
    
    
    Run

Does anybody have a similar issue with Nim / Xcode tools? Has the location of 
of Xcode tools changed?