Always use Unix Makefiles generator for Fortran projects

CMakeLists.txt

@@ -106,7 +106,6 @@ endif()
 # BEGIN external projects
 
 # External projects in order of dependencies; 'trivial' ones first
-drake_add_external(avl PUBLIC CMAKE)
 drake_add_external(bertini)
 drake_add_external(bullet PUBLIC CMAKE)
 drake_add_external(eigen PUBLIC CMAKE)
@@ -120,9 +119,12 @@ drake_add_external(snopt CMAKE)
 drake_add_external(spdlog PUBLIC CMAKE)
 drake_add_external(spotless PUBLIC CMAKE)
 drake_add_external(swigmake PUBLIC CMAKE)
-drake_add_external(xfoil PUBLIC CMAKE)
 drake_add_external(yalmip PUBLIC)
 
+# avl
+# The Ninja generator does not support Fortran.
+drake_add_external(avl PUBLIC CMAKE GENERATOR "Unix Makefiles")
+
 # cmake
 drake_add_external(cmake PUBLIC ALWAYS
   BUILD_COMMAND :
@@ -261,6 +263,10 @@ drake_add_external(director PUBLIC CMAKE
 drake_add_external(signalscope PUBLIC
   DEPENDS director)
 
+# xfoil
+# The Ninja generator does not support Fortran.
+drake_add_external(xfoil PUBLIC CMAKE GENERATOR "Unix Makefiles")
+
 # drake: For drake, list both compilation AND RUNTIME dependencies. Runtime
 # dependencies are needed because the drake project must configure only after
 # any dependencies used by MATLAB have been installed.

cmake/externals.cmake

@@ -180,7 +180,7 @@ macro(drake_add_cmake_external PROJECT)
     INDEPENDENT_STEP_TARGETS update
     BUILD_ALWAYS 1
     DEPENDS ${_ext_deps}
-    CMAKE_GENERATOR ${CMAKE_GENERATOR}
+    CMAKE_GENERATOR "${_ext_GENERATOR}"
     CMAKE_ARGS
       ${_ext_VERBOSE}
       ${_ext_PROPAGATE_CACHE}
@@ -249,6 +249,7 @@ endmacro()
 #   SOURCE_SUBDIR <dir> - Specify SOURCE_SUBDIR for external
 #   SOURCE_DIR <dir> - Override default SOURCE_DIR for external
 #   BINARY_DIR <dir> - Override default BINARY_DIR for external
+#   GENERATOR <gen> - Override default CMAKE_GENERATOR for external
 #
 #   PATCH_COMMAND <args...>
 #   CONFIGURE_COMMAND <args...>
@@ -280,6 +281,7 @@ function(drake_add_external PROJECT)
     SOURCE_SUBDIR
     SOURCE_DIR
     BINARY_DIR
+    GENERATOR
   )
   set(_ext_mv_args
     CMAKE_ARGS
@@ -290,6 +292,10 @@ function(drake_add_external PROJECT)
   cmake_parse_arguments(_ext
     "${_ext_flags}" "${_ext_sv_args}" "${_ext_mv_args}" ${ARGN})
 
+  if(NOT _ext_GENERATOR)
+    set(_ext_GENERATOR "${CMAKE_GENERATOR}")
+  endif()
+
   string(TOUPPER WITH_${PROJECT} _ext_project_option)
   if(_ext_ALWAYS)
     # Project is "always" enabled, but add a hidden option to turn it off; this
@@ -381,7 +387,7 @@ function(drake_add_external PROJECT)
 
     # Add external to download dependencies
     add_dependencies(download-all ${PROJECT}-update)
-  elseif(CMAKE_GENERATOR STREQUAL "Ninja" AND CMAKE_VERSION VERSION_LESS 3.7)
+  elseif(_ext_GENERATOR STREQUAL "Ninja" AND CMAKE_VERSION VERSION_LESS 3.7)
     # Due to a quirk of how the CMake Ninja generator computes dependencies,
     # all targets that contain a submodule update command, or depend on a
     # target that does, need to depend on the submodule-sync target, or the