cmake: export targets, allow building mechanisms via CMake, part 1

CMakeLists.txt

@@ -577,6 +577,9 @@ endif()
 # initialize CLI11 submodule
 cpp_cc_git_submodule(CLI11 BUILD PACKAGE CLI11 REQUIRED)
 
+# coreneuron targets will get propagated down from the subdirectory
+set(NRN_INSTALL_TARGETS nrniv_lib nocmodl)
+
 # =============================================================================
 # Enable NMODL code-generator support
 # =============================================================================
@@ -1104,6 +1107,37 @@ if(NRN_MACOS_BUILD AND NOT SKBUILD)
   nrn_macos_after_install()
 endif()
 
+# =============================================================================
+# Install CMake glue
+# =============================================================================
+configure_file(cmake/neuronMechMaker.cmake
+               "${PROJECT_BINARY_DIR}/lib/cmake/neuron/neuronMechMaker.cmake" COPYONLY)
+configure_file(cmake/mod_reg_nrn.cpp.in "${PROJECT_BINARY_DIR}/share/nrn/mod_reg_nrn.cpp.in"
+               COPYONLY)
+configure_file(cmake/mod_reg_corenrn.cpp.in
+               "${PROJECT_BINARY_DIR}/share/nrn/mod_reg_corenrn.cpp.in" COPYONLY)
+install(TARGETS ${NRN_INSTALL_TARGETS} ${CORENRN_INSTALL_TARGETS} EXPORT NeuronTargets)
+export(
+  EXPORT NeuronTargets
+  FILE ${PROJECT_BINARY_DIR}/lib/cmake/neuron/neuronTargets.cmake
+  NAMESPACE neuron::)
+
+install(
+  EXPORT NeuronTargets
+  FILE neuronTargets.cmake
+  NAMESPACE neuron::
+  DESTINATION lib/cmake/neuron)
+
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/cmake/neuronConfig.cmake.in
+               ${CMAKE_CURRENT_BINARY_DIR}/lib/cmake/neuron/neuronConfig.cmake @ONLY)
+
+install(FILES ${CMAKE_CURRENT_BINARY_DIR}/lib/cmake/neuron/neuronConfig.cmake
+        DESTINATION lib/cmake/neuron)
+install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/cmake/neuronMechMaker.cmake DESTINATION lib/cmake/neuron)
+
+install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/cmake/mod_reg_nrn.cpp.in
+              ${CMAKE_CURRENT_SOURCE_DIR}/cmake/mod_reg_corenrn.cpp.in DESTINATION share/nrn)
+
 # =============================================================================
 # Copy bash executable for windows
 # =============================================================================

cmake/mod_reg_corenrn.cpp.in

@@ -0,0 +1,16 @@
+#include <cstdio>
+namespace coreneuron {
+extern int nrnmpi_myid;
+extern int nrn_nobanner_;
+
+@MECH_DECLARE@
+
+void modl_reg() {
+  if (!nrn_nobanner_) if (nrnmpi_myid < 1) {
+    fprintf(stderr, " Additional mechanisms from files\n");
+    @MECH_PRINT@
+    fprintf(stderr, "\n\n");
+  }
+  @MECH_REGISTRE@
+}
+} //namespace coreneuron

cmake/mod_reg_nrn.cpp.in

@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include "hocdec.h"
+extern int nrnmpi_myid;
+extern int nrn_nobanner_;
+
+@MECH_DECLARE@
+
+extern "C" void modl_reg() {
+  if (!nrn_nobanner_) if (nrnmpi_myid < 1) {
+    fprintf(stderr, "Additional mechanisms from files\n");
+    @MECH_PRINT@
+    fprintf(stderr, "\n");
+  }
+  @MECH_REGISTRE@
+}
+

cmake/neuronConfig.cmake.in

@@ -0,0 +1,25 @@
+include(CMakeFindDependencyMacro)
+
+find_dependency(Threads)
+
+include("${CMAKE_CURRENT_LIST_DIR}/neuronTargets.cmake")
+
+get_filename_component(_dir "${CMAKE_CURRENT_LIST_FILE}" PATH)
+get_filename_component(_prefix "${_dir}/../../.." ABSOLUTE)
+
+set(NRN_ENABLE_CORENEURON @NRN_ENABLE_CORENEURON@)
+
+set(_NEURON_MAIN "${_prefix}/share/nrn/nrnmain.cpp")
+set(_NEURON_MAIN_INCLUDE_DIR "${_prefix}/include/nrncvode" "${_prefix}/include")
+set(_NEURON_MECH_REG "${_prefix}/share/nrn/mod_reg_nrn.cpp.in")
+
+set(_CORENEURON_BASE_MOD "${_prefix}/share/modfile")
+set(_CORENEURON_MAIN "${_prefix}/share/coreneuron/coreneuron.cpp")
+set(_CORENEURON_MECH_REG "${_prefix}/share/nrn/mod_reg_corenrn.cpp.in")
+set(_CORENEURON_MECH_ENG "${_prefix}/share/coreneuron/enginemech.cpp")
+set(_CORENEURON_RANDOM_INCLUDE "${_prefix}/include/coreneuron/utils/randoms" "${_prefix}/include")
+set(_CORENEURON_FLAGS @CORENRN_CXX_FLAGS@)
+
+find_program(NMODL nmodl REQUIRED)
+
+include(${CMAKE_CURRENT_LIST_DIR}/neuronMechMaker.cmake)