use bind/GetPythonConfig for cmd_build instead of its own separate code for that -- fixes building on mac..

Author: Randall C. O'Reilly

README.md

@@ -175,13 +175,25 @@ package hi exposes a few Go functions to be wrapped and used from Python.
 ```
 
 ### From the command line
+
 ```sh
+$ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:./
 $ gopy build -output=out -vm=`which python3` github.com/go-python/gopy/_examples/hi
 $ ls out
-build.py  go.py  hi.c  hi.go  hi_go.h  hi_go.so  hi.py  _hi.so*  __init__.py  Makefile
+Makefile  __init__.py  __pycache__/  _hi.so*  build.py  go.py  hi.c  hi.go  hi.py  hi_go.h  hi_go.so  patch-leaks.go
+```
 
+Note: the above may fail with link errors!  If so, go into the directory and use the auto-generated makefile:
+
+```sh
+$ cd out
+$ make
+```
+
+Once you get a clean build with no link errors, you can run it like this:
+
+```sh
 $ cd out
-$ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:./
 $ python3
 >>> import hi
 >>> dir(hi)

bind/gen.go

@@ -616,7 +616,7 @@ func (g *pyGen) genGoPreamble() {
 		pkgimport += fmt.Sprintf("\n\t%q", pi)
 	}
 	libcfg := func() string {
-		pycfg, err := getPythonConfig(g.vm)
+		pycfg, err := GetPythonConfig(g.vm)
 		if err != nil {
 			panic(err)
 		}
@@ -625,7 +625,7 @@ func (g *pyGen) genGoPreamble() {
 		pkgcfg := fmt.Sprintf(`
 #cgo CFLAGS: %s
 #cgo LDFLAGS: %s
-`, pycfg.cflags+exflags, pycfg.ldflags)
+`, pycfg.CFlags+exflags, pycfg.LdFlags)
 
 		return pkgcfg
 	}()
@@ -712,15 +712,15 @@ func (g *pyGen) genMakefile() {
 	gencmd := strings.Replace(g.cmdstr, "gopy build", "gopy gen", 1)
 	gencmd = CmdStrToMakefile(gencmd)
 
-	pycfg, err := getPythonConfig(g.vm)
+	pycfg, err := GetPythonConfig(g.vm)
 	if err != nil {
 		panic(err)
 	}
 
 	if g.mode == ModeExe {
-		g.makefile.Printf(MakefileExeTemplate, g.outname, g.cmdstr, gencmd, g.vm, g.libext, pycfg.cflags, pycfg.ldflags)
+		g.makefile.Printf(MakefileExeTemplate, g.outname, g.cmdstr, gencmd, g.vm, g.libext, pycfg.CFlags, pycfg.LdFlags)
 	} else {
-		g.makefile.Printf(MakefileTemplate, g.outname, g.cmdstr, gencmd, g.vm, g.libext, g.extraGccArgs, pycfg.cflags, pycfg.ldflags)
+		g.makefile.Printf(MakefileTemplate, g.outname, g.cmdstr, gencmd, g.vm, g.libext, g.extraGccArgs, pycfg.CFlags, pycfg.LdFlags)
 	}
 }
 

bind/utils.go

@@ -85,15 +85,20 @@ func isConstructor(sig *types.Signature) bool {
 	return false
 }
 
-type pyconfig struct {
-	version int
-	cflags  string
-	ldflags string
+type PyConfig struct {
+	Version int
+	CFlags  string
+	LdFlags string
 }
 
-// getPythonConfig returns the needed python configuration for the given
+// AllFlags returns CFlags + " " + LdFlags
+func (pc *PyConfig) AllFlags() string {
+	return strings.TrimSpace(pc.CFlags) + " " + strings.TrimSpace(pc.LdFlags)
+}
+
+// GetPythonConfig returns the needed python configuration for the given
 // python VM (python, python2, python3, pypy, etc...)
-func getPythonConfig(vm string) (pyconfig, error) {
+func GetPythonConfig(vm string) (PyConfig, error) {
 	code := `import sys
 import distutils.sysconfig as ds
 import json
@@ -122,7 +127,7 @@ else:
 }))
 `
 
-	var cfg pyconfig
+	var cfg PyConfig
 	bin, err := exec.LookPath(vm)
 	if err != nil {
 		return cfg, errors.Wrapf(err, "could not locate python vm %q", vm)
@@ -161,11 +166,11 @@ else:
 		raw.LibPy = raw.LibPy[len("lib"):]
 	}
 
-	cfg.version = raw.Version
-	cfg.cflags = strings.Join([]string{
+	cfg.Version = raw.Version
+	cfg.CFlags = strings.Join([]string{
 		"-I" + raw.IncDir,
 	}, " ")
-	cfg.ldflags = strings.Join([]string{
+	cfg.LdFlags = strings.Join([]string{
 		"-L" + raw.LibDir,
 		"-l" + raw.LibPy,
 		raw.ShLibs,

bind/utils_test.go

@@ -85,7 +85,7 @@ func TestPythonConfig(t *testing.T) {
 		},
 	} {
 		t.Run(tc.vm, func(t *testing.T) {
-			cfg, err := getPythonConfig(tc.vm)
+			cfg, err := GetPythonConfig(tc.vm)
 			if err != nil {
 				t.Fatal(err)
 			}

cmd_build.go

@@ -120,6 +120,8 @@ func runBuild(mode bind.BuildMode, odir, outname, cmdstr, vm, mainstr string, sy
 		return err
 	}
 
+	pycfg, err := bind.GetPythonConfig(vm)
+
 	if mode == bind.ModeExe {
 		of, err := os.Create(buildname + ".h") // overwrite existing
 		fmt.Fprintf(of, "typedef uint8_t bool;\n")
@@ -198,32 +200,32 @@ func runBuild(mode bind.BuildMode, odir, outname, cmdstr, vm, mainstr string, sy
 			return err
 		}
 		cccmd := strings.TrimSpace(string(cccmdb))
-		var cflags, ldflags []byte
-		if runtime.GOOS != "windows" {
-			fmt.Printf("%v-config --cflags\n", vm)
-			cmd = exec.Command(vm+"-config", "--cflags") // TODO: need minor version!
-			cflags, err = cmd.CombinedOutput()
-			if err != nil {
-				fmt.Printf("cmd had error: %v  output:\n%v\n", err, string(cflags))
-				return err
-			}
-
-			fmt.Printf("%v-config --ldflags\n", vm)
-			cmd = exec.Command(vm+"-config", "--ldflags")
-			ldflags, err = cmd.CombinedOutput()
-			if err != nil {
-				fmt.Printf("cmd had error: %v  output:\n%v\n", err, string(ldflags))
-				return err
-			}
-		}
+		// var cflags, ldflags []byte
+		// if runtime.GOOS != "windows" {
+		// 	fmt.Printf("%v-config --cflags\n", vm)
+		// 	cmd = exec.Command(vm+"-config", "--cflags") // TODO: need minor version!
+		// 	cflags, err = cmd.CombinedOutput()
+		// 	if err != nil {
+		// 		fmt.Printf("cmd had error: %v  output:\n%v\n", err, string(cflags))
+		// 		return err
+		// 	}
+		//
+		// 	fmt.Printf("%v-config --ldflags\n", vm)
+		// 	cmd = exec.Command(vm+"-config", "--ldflags")
+		// 	ldflags, err = cmd.CombinedOutput()
+		// 	if err != nil {
+		// 		fmt.Printf("cmd had error: %v  output:\n%v\n", err, string(ldflags))
+		// 		return err
+		// 	}
+		// 	fmt.Printf("build cmd: %s\nldflags: %s\n", cmd, ldflags)
+		// }
 		extext := libExt
 		if runtime.GOOS == "windows" {
 			extext = ".pyd"
 		}
 		modlib := "_" + outname + extext
 		gccargs := []string{outname + ".c", extraGccArgs, outname + "_go" + libExt, "-o", modlib}
-		gccargs = append(gccargs, strings.Split(strings.TrimSpace(string(cflags)), " ")...)
-		gccargs = append(gccargs, strings.Split(strings.TrimSpace(string(ldflags)), " ")...)
+		gccargs = append(gccargs, strings.Fields(pycfg.AllFlags())...)
 		gccargs = append(gccargs, "-fPIC", "--shared", "-Ofast")
 		if !symbols {
 			gccargs = append(gccargs, "-s")