Try and make work on OSX. Add the CI matrix.

.github/workflows/ccpp.yml

@@ -0,0 +1,23 @@
+name: C/C++ CI
+
+on: [push]
+
+jobs:
+  build-linux:
+    runs-on: ubuntu-20.04
+    steps:
+    - uses: actions/checkout@v1
+    - name: apt
+      run: sudo apt update && sudo apt install bison flex ninja-build
+    - name: make
+      run: make
+
+  build-macos:
+    runs-on: macos-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: brew
+      run: brew install ninja
+    - name: make
+      run: make
+

mach/pdp/cv/cv.c

@@ -12,6 +12,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 struct exec {
 	short a_magic;
@@ -52,6 +53,11 @@ int	outputfile_created;
 FILE	*output;
 int	rom_in_text;
 
+static cv_int2();
+static fatal();
+static emits();
+static emit_symtab();
+
 char *program ;
 
 char flag ;

mach/proto/cg/compute.c

@@ -17,6 +17,7 @@
 #include "glosym.h"
 #include "extern.h"
 #include "subr.h"
+#include "regvar.h"
 #include "salloc.h"
 
 

mach/proto/cg/gencode.h

@@ -17,6 +17,6 @@ void gencode(register char *code);
 void genexpr(int nodeno);
 void gennl(void);
 void prtoken(token_p tp);
-
+void regreturn(void);
 
 #endif /* GENCODE_H_ */

util/LLgen/src/gencode.c

@@ -20,6 +20,7 @@
 
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 # include "types.h"
 # include "io.h"
 # include "extern.h"

util/int/data.h

@@ -19,6 +19,7 @@ void dt_stip(register ptr addr, ptr ap);
 void dt_stf(register ptr addr, double f, register size n);
 #endif
 
+ptr dt_ldip(ptr addr);
 ptr dt_lddp(register ptr addr);
 unsigned long dt_ldu(register ptr addr, size n);
 unsigned long dt_lduw(register ptr addr);

util/int/io.h

@@ -8,9 +8,10 @@
 #ifndef IO_H_
 #define IO_H_
 
-void fatal(char *fmt, ...);
-void message(char *fmt, ...);
-void init_ofiles(int firsttime);
-void close_down(int rc);
+extern void fatal(char *fmt, ...);
+extern void message(char *fmt, ...);
+extern void init_ofiles(int firsttime);
+extern void close_down(int rc);
+extern void incr_mess_id(void);
 
 #endif /* IO_H_ */

util/int/switch.c

@@ -11,6 +11,8 @@
 #include	"trap.h"
 #include	"warn.h"
 #include	"switch.h"
+#include	"stack.h"
+#include	"data.h"
 
 void do_instr(unsigned int opcode)
 {