$ ll
total 2
-rw-r--r--  1 izzy  staff   6.4K 11 Feb 21:10 add.scm
-rw-r--r--  1 izzy  staff   261B 11 Feb 21:15 useadd.c

$ cat add.scm
(export add)
(define (add x y)
  (displayln "Inside add!")
  (+ x y))


$ cat useadd.c

#include <stdio.h>

extern int add(int x, int y);

int main()
{
    printf("in add. result is: %d", add(5, 7));
    return add(5, 7);
    }

$ gsc -c add.scm # This generates add.c.


$ glibtool --tag=CC --mode=compile gcc -I/usr/local/gambit/current/include -g -O -c add.c

glibtool: compile:  gcc -I/usr/local/gambit/current/include -g -O -c add.c  -fno-common -DPIC -o .libs/add.o
glibtool: compile:  gcc -I/usr/local/gambit/current/include -g -O -c add.c -o add.o >/dev/null 2>&1


$ glibtool --tag=CC --mode=link gcc -L/usr/local/gambit/current/lib -g -O -o libadd.la add.lo -rpath /usr/local/lib -lgambit

glibtool: link: clang -dynamiclib -Wl,-undefined -Wl,dynamic_lookup -o .libs/libadd.0.dylib  .libs/add.o   -L/usr/local/gambit/current/lib -lgambit  -g -O   -install_name  /usr/local/lib/libadd.0.dylib -compatibility_version 1 -current_version 1.0 -Wl,-single_module
glibtool: link: (cd ".libs" && rm -f "libadd.dylib" && ln -s "libadd.0.dylib" "libadd.dylib")
glibtool: link: ar cru .libs/libadd.a  add.o
glibtool: link: ranlib .libs/libadd.a
glibtool: link: ( cd ".libs" && rm -f "libadd.la" && ln -s "../libadd.la" "libadd.la" )


$ glibtool --tag=CC --mode=compile gcc -L. -g -O -c useadd.c

glibtool: compile:  gcc -L. -g -O -c useadd.c  -fno-common -DPIC -o .libs/useadd.o
clang: warning: argument unused during compilation: '-L.' [-Wunused-command-line-argument]
glibtool: compile:  gcc -L. -g -O -c useadd.c -o useadd.o >/dev/null 2>&1

$ ll
total 128
-rw-r--r--  1 izzy  staff   6.4K 11 Feb 21:10 add.c
-rw-r--r--  1 izzy  staff   261B 11 Feb 21:15 add.lo
-rw-r--r--  1 izzy  staff    31K 11 Feb 21:15 add.o
-rw-r--r--  1 izzy  staff    70B 11 Feb 15:52 add.scm
-rw-r--r--  1 izzy  staff   943B 11 Feb 21:18 libadd.la
-rw-r--r--  1 izzy  staff   139B 11 Feb 20:51 useadd.c
-rw-r--r--  1 izzy  staff   270B 11 Feb 21:21 useadd.lo
-rw-r--r--  1 izzy  staff   2.2K 11 Feb 21:21 useadd.o

ls -l .libs
total 168
-rw-r--r--  1 izzy  staff  31904 11 Feb 21:15 add.o
-rwxr-xr-x  1 izzy  staff   9852 11 Feb 21:18 libadd.0.dylib
-rw-r--r--  1 izzy  staff  32096 11 Feb 21:18 libadd.a
lrwxr-xr-x  1 izzy  staff     14 11 Feb 21:18 libadd.dylib -> libadd.0.dylib
lrwxr-xr-x  1 izzy  staff     12 11 Feb 21:18 libadd.la -> ../libadd.la
-rw-r--r--  1 izzy  staff    944 11 Feb 21:18 libadd.lai
-rw-r--r--  1 izzy  staff   2268 11 Feb 21:21 useadd.o

$ glibtool --tag=CC --mode=link gcc -g -O -o useadd useadd.o libadd.la

glibtool: link: gcc -g -O -o .libs/useadd useadd.o  ./.libs/libadd.dylib -L/usr/local/gambit/current/lib -lgambit
Undefined symbols for architecture x86_64:
  "_add", referenced from:
      _main in useadd.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)