Support pkg-config (#253)

CMakeLists.txt

@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.13 FATAL_ERROR)
 project(sherpa-onnx)
 
-set(SHERPA_ONNX_VERSION "1.7.0")
+set(SHERPA_ONNX_VERSION "1.7.1")
 
 # Disable warning about
 #
@@ -167,3 +167,22 @@ if(SHERPA_ONNX_ENABLE_C_API)
   add_subdirectory(c-api-examples)
 endif()
 message(STATUS "CMAKE_CXX_FLAGS: ${CMAKE_CXX_FLAGS}")
+
+if(NOT BUILD_SHARED_LIBS)
+  if(APPLE)
+    set(SHERPA_ONNX_PKG_CONFIG_EXTRA_LIBS "-lc++")
+  endif()
+
+  if(UNIX AND NOT APPLE)
+    set(SHERPA_ONNX_PKG_CONFIG_EXTRA_LIBS "-lstdc++ -lm")
+  endif()
+endif()
+
+# See https://people.freedesktop.org/~dbn/pkg-config-guide.html
+configure_file(cmake/sherpa-onnx.pc.in ${PROJECT_BINARY_DIR}/sherpa-onnx.pc @ONLY)
+install(
+  FILES
+    ${PROJECT_BINARY_DIR}/sherpa-onnx.pc
+  DESTINATION
+    .
+)