I'm trying to pass an environment variable to an external project in my CMakeLists.txt without any success.
In this case, I have a dependency to mbedtls library which is downloaded and built in my cmake. In Linux this works as intended, however in a Windows environment, I need to pass a variable WINDOWS_BUILD=1 to the make environment.
I have tried to add a CONFIGURE_COMMAND to a batch file which sets this environment variable in the ExternalProject_Add(), however this does not work. If I manually go into the automatically downloaded mbedtls folder and write
$ make WINDOWS_BUILD=1
it works as intended, however I want to build everything from CMake environment. Any takes?