extmod/extmod.cmake: Require components to be explicitly enabled.

Otherwise include directories are added unconditionally to the build
variables if the component (submodule) is checked out.  This can lead to,
eg, the esp32 build using lib/lwip header files, instead of lwip header
files from the IDF.

Fixes issue #8727.
Signed-off-by: Damien George <damien@micropython.org>

extmod/extmod.cmake

@@ -54,9 +54,9 @@ set(MICROPY_SOURCE_EXTMOD
 
 # Library for btree module and associated code
 
-set(MICROPY_LIB_BERKELEY_DIR "${MICROPY_DIR}/lib/berkeley-db-1.xx")
+if(MICROPY_PY_BTREE)
+    set(MICROPY_LIB_BERKELEY_DIR "${MICROPY_DIR}/lib/berkeley-db-1.xx")
 
-if(EXISTS "${MICROPY_LIB_BERKELEY_DIR}/btree/bt_close.c")
     add_library(micropy_extmod_btree OBJECT
         ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_close.c
         ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_conv.c
@@ -100,11 +100,11 @@ endif()
 
 # Library for mbedtls
 
-set(MICROPY_LIB_MBEDTLS_DIR "${MICROPY_DIR}/lib/mbedtls")
-
-if(EXISTS "${MICROPY_LIB_MBEDTLS_DIR}/library/aes.c")
+if(MICROPY_SSL_MBEDTLS)
     add_library(micropy_lib_mbedtls INTERFACE)
 
+    set(MICROPY_LIB_MBEDTLS_DIR "${MICROPY_DIR}/lib/mbedtls")
+
     target_include_directories(micropy_lib_mbedtls INTERFACE
         ${MICROPY_LIB_MBEDTLS_DIR}/include
     )
@@ -194,11 +194,11 @@ endif()
 
 # Library for lwIP network stack
 
-set(MICROPY_LIB_LWIP_DIR "${MICROPY_DIR}/lib/lwip/src")
-
-if(EXISTS "${MICROPY_LIB_LWIP_DIR}/core/def.c")
+if(MICROPY_PY_LWIP)
     add_library(micropy_lib_lwip INTERFACE)
 
+    set(MICROPY_LIB_LWIP_DIR "${MICROPY_DIR}/lib/lwip/src")
+
     target_include_directories(micropy_lib_lwip INTERFACE
         ${MICROPY_LIB_LWIP_DIR}/include
     )

ports/esp32/main/CMakeLists.txt

@@ -7,6 +7,10 @@ endif()
 include(${MICROPY_DIR}/py/py.cmake)
 
 if(NOT CMAKE_BUILD_EARLY_EXPANSION)
+    # Enable extmod components that will be configured by extmod.cmake.
+    # A board may also have enabled additional components.
+    set(MICROPY_PY_BTREE ON)
+
     include(${MICROPY_DIR}/py/usermod.cmake)
     include(${MICROPY_DIR}/extmod/extmod.cmake)
 endif()

ports/rp2/CMakeLists.txt

@@ -43,6 +43,10 @@ if(NOT PICO_BOARD)
     string(TOLOWER ${MICROPY_BOARD} PICO_BOARD)
 endif()
 
+# Enable extmod components that will be configured by extmod.cmake.
+# A board may also have enabled additional components.
+set(MICROPY_SSL_MBEDTLS ON)
+
 # Include component cmake fragments
 include(${MICROPY_DIR}/py/py.cmake)
 include(${MICROPY_DIR}/extmod/extmod.cmake)