Split libpkl libraries between shared and static libs (#1812)

This adds a `libpkl-static.pc` so pkg-config users can link either
statically or dynamically via `pkg-config --libs libpkl`, or
`pkg-config --libs libpkl-static`.

Additionally, this fixes an issue where the replace tokens wasn't
doing anything, leaving the `@version@` token intact in the archive.

Additionally, this adds an `-install_name` when building the dylib for macOS.

Co-authored-by: Islon Scherer <islonscherer@gmail.com>

libpkl/libpkl.gradle.kts

@@ -251,16 +251,11 @@ val buildSharedLibrary =
       frameworks.addAll("Foundation", "CoreServices")
       linkerFlags.addAll("-current_version", project.version.toString())
       linkerFlags.addAll("-compatibility_version", "0.1.0")
-
-      // libpkl_internal_s bundles Native Image's own JNI-named implementations of JDK native
-      // methods (e.g. Java_sun_nio_ch_UnixFileDispatcherImpl_write0), which by default get
-      // exported with global visibility. Loading libpkl.dylib into a JVM process (e.g. via JNA)
-      // then lets the host JVM's own native-method resolution bind to these internal
-      // implementations instead of the JDK's real ones, silently corrupting unrelated file I/O.
-      // Restrict the dylib's exported symbols to just the public pkl_* API to prevent this.
+      // prevent JNI symbols from being exported and clobbering the symbol table
       val exportedSymbolsFile = file("src/main/c/pkl.exported_symbols")
       inputs.file(exportedSymbolsFile)
       linkerFlags.addAll("-exported_symbols_list", exportedSymbolsFile.absolutePath)
+      compilerArgs.addAll("-install_name", "@rpath/libpkl.dylib")
     }
 
     if (targetMachine.os.isWindows) {
@@ -276,9 +271,7 @@ val buildSharedLibrary =
 
     if (targetMachine.os.isLinux) {
       libraries.add("dl")
-
-      // Same symbol-collision hazard as the macOS case above (see comment there), but scoped via
-      // a GNU ld version script instead of an exported-symbols list.
+      // prevent JNI symbols from being exported and clobbering the symbol table
       val versionScriptFile = file("src/main/c/pkl.map")
       inputs.file(versionScriptFile)
       linkerFlags.add("--version-script=${versionScriptFile.absolutePath}")
@@ -317,7 +310,7 @@ val distZip =
     into(baseName)
   }
 
-tasks.assembleNative { dependsOn(distZip, distTar) }
+tasks.assembleNative { dependsOn(distZip, distTar, processFiles) }
 
 val processFiles =
   tasks.register<Copy>("processFiles") {
@@ -329,9 +322,23 @@ val processFiles =
     includeEmptyDirs = true
     into(buildInfo.targetMachine.outputDir)
 
-    filesMatching("libpkl.pc") {
-      filter<ReplaceTokens>("tokens" to mapOf("version" to buildInfo.pklVersion))
+    val tokens = buildMap {
+      this["version"] = buildInfo.pklVersion
+      this["static_lib_filename"] = "libpkl.${buildInfo.os.staticLibraryExtension}"
+      this["extra_static_libs"] =
+        when {
+          buildInfo.os.isMacOS -> " -lz -framework Foundation -framework CoreServices"
+          buildInfo.os.isWindows -> ""
+          else -> " -lz"
+        }
+      this["extra_shared_libs"] =
+        when {
+          buildInfo.os.isMacOS -> " -lpkl"
+          buildInfo.os.isWindows -> " -l:libpkl_dll.lib"
+          else -> " -lpkl"
+        }
     }
+    filesMatching("**/libpkl*.pc") { filter<ReplaceTokens>("tokens" to tokens) }
   }
 
 val testNativeJava =
@@ -428,8 +435,6 @@ val compileNativeTestDynamic =
       libraryFiles.from(buildInfo.targetMachine.libraryDir.map { it.file("libpkl_dll.lib") })
     } else {
       libraries.add("pkl")
-      libraries.add("z")
-      libraries.add("pthread")
       // Bake the library's location into the test executable so the dynamic loader can find
       // libpkl.so/libpkl.dylib without needing LD_LIBRARY_PATH/DYLD_LIBRARY_PATH set at run time.
       linkerFlags.add("-rpath")

libpkl/src/main/files/lib/pkgconfig/libpkl-static.pc

@@ -0,0 +1,11 @@
+prefix=${pcfiledir}/../..
+exec_prefix=${prefix}
+libdir=${exec_prefix}/lib
+includedir=${prefix}/include
+
+Name: libpkl
+Description: C library for calling into Pkl's message passing API.
+URL: https://pkl-lang.org/main/current/libpkl/index.html
+Version: @version@
+Libs: ${libdir}/@static_lib_filename@@extra_static_libs@
+Cflags: -I${includedir}

libpkl/src/main/files/lib/pkgconfig/libpkl.pc

@@ -7,5 +7,5 @@ Name: libpkl
 Description: C library for calling into Pkl's message passing API.
 URL: https://pkl-lang.org/main/current/libpkl/index.html
 Version: @version@
-Libs: -L${libdir} -lpkl -lz -lpthread
+Libs: -L${libdir}@extra_shared_libs@
 Cflags: -I${includedir}