Add example to modify input source

examples/configure_modify_input_source/BUILD.bazel

@@ -0,0 +1,18 @@
+load("@rules_cc//cc:defs.bzl", "cc_test")
+load("@rules_foreign_cc//foreign_cc:defs.bzl", "configure_make")
+
+configure_make(
+    name = "simple",
+    configure_in_place = True,
+    lib_source = "//configure_modify_input_source/simple_lib:simple_srcs",
+    targets = [
+        "simple",
+        "install",
+    ],
+)
+
+cc_test(
+    name = "test",
+    srcs = ["testSimple.c"],
+    deps = [":simple"],
+)

examples/configure_modify_input_source/simple_lib/BUILD.bazel

@@ -0,0 +1,5 @@
+filegroup(
+    name = "simple_srcs",
+    srcs = glob(["**"]),
+    visibility = ["//visibility:public"],
+)

examples/configure_modify_input_source/simple_lib/Makefile.in

@@ -0,0 +1,7 @@
+simple: ./src/simple.c
+	$(CC) $(CPPFLAGS) $(LDFLAGS) -o simple.a -c ./src/simple.c -I./include -I.
+install:
+	mkdir -p simple
+	mkdir -p simple/lib
+	cp simple.a ./simple/lib/simple.a
+	cp -r ./include ./simple

examples/configure_modify_input_source/simple_lib/configure

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+# Slightly contrived example of a tool
+# that resolves the symlinks to the real file
+# and attempts to modify it
+# (Using perl here for replacement to avoid difference in in-place
+# arguments on macOS sed)
+# Note that perl -i would just replace the symlink
+# if used directly
+
+perl -i -pe 's/42/0/' $(readlink src/simple.c)
+echo "CC = $CC" > Makefile
+echo "CPPFLAGS = $CPPFLAGS" >> Makefile
+echo "LDFLAGS = $LDFLAGS" >> Makefile
+cat Makefile.in >> Makefile

examples/configure_modify_input_source/simple_lib/include/simple.h

@@ -0,0 +1,6 @@
+#ifndef SIMPLE_H_
+#define SIMPLE_H_ (1)
+
+int simpleFun(void);
+
+#endif // SIMPLE_H_

examples/configure_modify_input_source/simple_lib/src/simple.c

@@ -0,0 +1,5 @@
+#include "simple.h"
+
+int simpleFun(void) {
+  return 42;
+}

examples/configure_modify_input_source/testSimple.c

@@ -0,0 +1,5 @@
+#include "simple.h"
+
+int main(int argc, char **argv) {
+  return simpleFun();
+}