CMakeLists.txt: allow disabling Python support

In some cases, even if Swig is found and Python3 is found, it may not
be desirable to build Python support in avrdude, so this commit adds
an ENABLE_PYTHON_SUPPORT option to be able to explicitly disable using
Python support (unfortunately CMake doesn't allow passing arguments
that would prevent it from finding Swig/Python 3 if available).

To preserve existing behavior, this option defaults to enabled (ON).

Signed-off-by: Thomas Petazzoni <[email protected]>

Author: tpetazzoni

CMakeLists.txt

@@ -34,6 +34,7 @@ option(USE_EXTERNAL_LIBS "Use external libraries from AVRDUDE GitHub repositorie
 option(USE_LIBUSBWIN32 "Prefer libusb-win32 over libusb" OFF)
 option(DEBUG_CMAKE "Enable debugging output for this CMake project" OFF)
 option(BUILD_SHARED_LIBS "Build shared libraries" OFF)
+option(ENABLE_PYTHON_SUPPORT "Enable Python support" ON)
 
 if(WIN32)
     # Prefer static libraries over DLLs on Windows
@@ -281,14 +282,16 @@ if(HAVE_LINUXGPIO)
 endif()
 
 # -------------------------------------
-# Find SWIG
-find_package(SWIG 4.0 COMPONENTS python)
-if(SWIG_FOUND)
-  find_package(Python3 COMPONENTS Interpreter Development)
-  if(PYTHON3_FOUND)
-    set(HAVE_SWIG 1)
-  else()
-    message(STATUS "Found SWIG but no Python3 header/library; cannot use SWIG")
+# Find SWIG/Python3 if needed
+if(ENABLE_PYTHON_SUPPORT)
+  find_package(SWIG 4.0 COMPONENTS python)
+  if(SWIG_FOUND)
+    find_package(Python3 COMPONENTS Interpreter Development)
+    if(PYTHON3_FOUND)
+      set(HAVE_SWIG 1)
+    else()
+      message(STATUS "Found SWIG but no Python3 header/library; cannot use SWIG")
+    endif()
   endif()
 endif()