Add support for system build and installation

CMakeLists.txt

@@ -4,67 +4,81 @@
 cmake_minimum_required(VERSION 3.26)
 project(piper LANGUAGES C CXX)
 
-include(ExternalProject)
+option(USE_SYSTEM_ESPEAKNG "Use system-installed espeak-ng instead of building from source" OFF)
 
 # scikit-build-core will forward Python_* variables
 find_package(Python COMPONENTS Development.Module Development.SABIModule REQUIRED)
 
-# Install location for espeak-ng
-set(ESPEAKNG_BUILD_DIR ${CMAKE_BINARY_DIR}/espeak_ng)
-set(ESPEAKNG_INSTALL_DIR ${CMAKE_BINARY_DIR}/espeak_ng-install)
+if(NOT USE_SYSTEM_ESPEAKNG)
+    include(ExternalProject)
 
-if(WIN32)
-    # Special handling for Windows
-    set(ESPEAKNG_STATIC_LIB ${ESPEAKNG_INSTALL_DIR}/lib/espeak-ng.lib)
-    set(UCD_STATIC_LIB ${ESPEAKNG_BUILD_DIR}/src/espeak_ng_external-build/src/ucd-tools/ucd.lib)
-else()
-    set(ESPEAKNG_STATIC_LIB ${ESPEAKNG_INSTALL_DIR}/lib/libespeak-ng.a)
-    set(UCD_STATIC_LIB ${ESPEAKNG_BUILD_DIR}/src/espeak_ng_external-build/src/ucd-tools/libucd.a)
-endif()
+    # Install location for espeak-ng
+    set(ESPEAKNG_BUILD_DIR ${CMAKE_BINARY_DIR}/espeak_ng)
+    set(ESPEAKNG_INSTALL_DIR ${CMAKE_BINARY_DIR}/espeak_ng-install)
 
-ExternalProject_Add(espeak_ng_external
-    GIT_REPOSITORY https://github.com/espeak-ng/espeak-ng.git
-    GIT_TAG 724808c  # 2026-Apr-06
-    PREFIX ${ESPEAKNG_BUILD_DIR}
-    CMAKE_ARGS
-        -DCMAKE_INSTALL_PREFIX=${ESPEAKNG_INSTALL_DIR}
-        -DBUILD_SHARED_LIBS:BOOL=OFF
-        -DCMAKE_POSITION_INDEPENDENT_CODE:BOOL=ON
-        -DUSE_ASYNC:BOOL=OFF
-        -DUSE_MBROLA:BOOL=OFF
-        -DUSE_LIBSONIC:BOOL=OFF
-        -DUSE_LIBPCAUDIO:BOOL=OFF
-        -DUSE_KLATT:BOOL=OFF
-        -DUSE_SPEECHPLAYER:BOOL=OFF
-        -DEXTRA_cmn:BOOL=ON
-        -DEXTRA_ru:BOOL=ON
-        # Need to explicitly add ucd include directory for CI
-        "-DCMAKE_C_FLAGS=-D_FILE_OFFSET_BITS=64 -I${ESPEAKNG_BUILD_DIR}/src/espeak_ng_external/src/ucd-tools/src/include"
-        "-DCMAKE_CXX_FLAGS=-D_FILE_OFFSET_BITS=64 -I${ESPEAKNG_BUILD_DIR}/src/espeak_ng_external/src/ucd-tools/src/include"
-    BUILD_BYPRODUCTS
-        ${ESPEAKNG_STATIC_LIB}
-        ${UCD_STATIC_LIB}
-    UPDATE_DISCONNECTED TRUE
-)
+    if(WIN32)
+        # Special handling for Windows
+        set(ESPEAKNG_STATIC_LIB ${ESPEAKNG_INSTALL_DIR}/lib/espeak-ng.lib)
+        set(UCD_STATIC_LIB ${ESPEAKNG_BUILD_DIR}/src/espeak_ng_external-build/src/ucd-tools/ucd.lib)
+    else()
+        set(ESPEAKNG_STATIC_LIB ${ESPEAKNG_INSTALL_DIR}/lib/libespeak-ng.a)
+        set(UCD_STATIC_LIB ${ESPEAKNG_BUILD_DIR}/src/espeak_ng_external-build/src/ucd-tools/libucd.a)
+    endif()
 
-include_directories(
-    ${ESPEAKNG_INSTALL_DIR}/include
-)
+    ExternalProject_Add(espeak_ng_external
+        GIT_REPOSITORY https://github.com/espeak-ng/espeak-ng.git
+        GIT_TAG 724808c  # 2026-Apr-06
+        PREFIX ${ESPEAKNG_BUILD_DIR}
+        CMAKE_ARGS
+            -DCMAKE_INSTALL_PREFIX=${ESPEAKNG_INSTALL_DIR}
+            -DBUILD_SHARED_LIBS:BOOL=OFF
+            -DCMAKE_POSITION_INDEPENDENT_CODE:BOOL=ON
+            -DUSE_ASYNC:BOOL=OFF
+            -DUSE_MBROLA:BOOL=OFF
+            -DUSE_LIBSONIC:BOOL=OFF
+            -DUSE_LIBPCAUDIO:BOOL=OFF
+            -DUSE_KLATT:BOOL=OFF
+            -DUSE_SPEECHPLAYER:BOOL=OFF
+            -DEXTRA_cmn:BOOL=ON
+            -DEXTRA_ru:BOOL=ON
+            # Need to explicitly add ucd include directory for CI
+            "-DCMAKE_C_FLAGS=-D_FILE_OFFSET_BITS=64 -I${ESPEAKNG_BUILD_DIR}/src/espeak_ng_external/src/ucd-tools/src/include"
+            "-DCMAKE_CXX_FLAGS=-D_FILE_OFFSET_BITS=64 -I${ESPEAKNG_BUILD_DIR}/src/espeak_ng_external/src/ucd-tools/src/include"
+        BUILD_BYPRODUCTS
+            ${ESPEAKNG_STATIC_LIB}
+            ${UCD_STATIC_LIB}
+        UPDATE_DISCONNECTED TRUE
+    )
+
+    include_directories(
+        ${ESPEAKNG_INSTALL_DIR}/include
+    )
+else()
+    find_package(PkgConfig REQUIRED)
+    pkg_check_modules(ESPEAKNG REQUIRED IMPORTED_TARGET espeak-ng)
+endif()
 
 # espeak bridge
 add_library(espeakbridge MODULE
     src/piper/espeakbridge.c
 )
 
-add_dependencies(espeakbridge espeak_ng_external)
-target_link_libraries(espeakbridge
-    ${ESPEAKNG_STATIC_LIB}
-    ${UCD_STATIC_LIB}
-    Python::SABIModule
-)
-target_include_directories(espeakbridge PRIVATE
-    ${ESPEAKNG_INSTALL_DIR}/include
-)
+if(NOT USE_SYSTEM_ESPEAKNG)
+    add_dependencies(espeakbridge espeak_ng_external)
+    target_link_libraries(espeakbridge
+        ${ESPEAKNG_STATIC_LIB}
+        ${UCD_STATIC_LIB}
+        Python::SABIModule
+    )
+    target_include_directories(espeakbridge PRIVATE
+        ${ESPEAKNG_INSTALL_DIR}/include
+    )
+else()
+    target_link_libraries(espeakbridge
+        PkgConfig::ESPEAKNG
+        Python::SABIModule
+    )
+endif()
 
 if(WIN32)
     # Fix dll thunk issue (__imp_SYMBOL not found)
@@ -86,12 +100,14 @@ install(TARGETS espeakbridge
     RUNTIME DESTINATION .
 )
 
-# Copy espeak-ng-data
-set(DATA_SRC ${CMAKE_BINARY_DIR}/espeak_ng-install/share/espeak-ng-data)
-set(DATA_DST ${CMAKE_CURRENT_SOURCE_DIR}/src/piper/espeak-ng-data)
+# Copy espeak-ng-data (skipped when using system espeak-ng)
+if(NOT USE_SYSTEM_ESPEAKNG)
+    set(DATA_SRC ${CMAKE_BINARY_DIR}/espeak_ng-install/share/espeak-ng-data)
+    set(DATA_DST ${CMAKE_CURRENT_SOURCE_DIR}/src/piper/espeak-ng-data)
 
-add_custom_target(copy_espeak_ng_data ALL
-    COMMAND ${CMAKE_COMMAND} -E copy_directory ${DATA_SRC} ${DATA_DST}
-    DEPENDS espeak_ng_external
-    COMMENT "Copying espeak-ng-data after espeak-ng external project builds"
-)
+    add_custom_target(copy_espeak_ng_data ALL
+        COMMAND ${CMAKE_COMMAND} -E copy_directory ${DATA_SRC} ${DATA_DST}
+        DEPENDS espeak_ng_external
+        COMMENT "Copying espeak-ng-data after espeak-ng external project builds"
+    )
+endif()