Script to test compatibility_version behaviour

compatver.sh

#!/bin/sh

CC=${CC-clang}

echo '#include <stdio.h>
#include "lib.h"

int libcall(void) {
    printf("working\\n");
    return 0;
}
' > ./lib.c

echo 'int libcall(void);
' > ./lib.h

echo '#include "lib.h"
int main(void)
{
    libcall();
    return 0;
}
' > main.c

$CC -c lib.c -o lib.o
$CC -dynamiclib -current_version 1.0.0 -compatibility_version 1.0.0 \
    -install_name '@executable_path/lib.1.dylib' lib.o -o lib.1.0.0.dylib
$CC -dynamiclib -current_version 2.0.0 -compatibility_version 2.0.0 \
    -install_name '@executable_path/lib.1.dylib' lib.o -o lib.2.0.0.dylib

ln -sf ./lib.1.0.0.dylib ./lib.1.dylib
$CC main.c ./lib.1.dylib -o testprog
echo "Built against lib 1.0.0; running with lib 1.0.0"
./testprog

echo "Built against lib 1.0.0; running with lib 2.0.0"
ln -sf ./lib.2.0.0.dylib ./lib.1.dylib
./testprog

$CC main.c ./lib.1.dylib -o testprog
echo "Built against lib 2.0.0; running with lib 2.0.0"
./testprog

ln -sf ./lib.1.0.0.dylib ./lib.1.dylib
echo "Built against lib 2.0.0; running with lib 1.0.0"
./testprog