Link eeschema with ngspice DLL

Adds a link-time dependency for libngspice, so that other tools may
detect ngspice as a KiCad dependency.

The library is still loaded with dlopen() as it gives a way to reload it
in case of problems. The DLL name is recognized during CMake
configuration and used to load the library at runtime.

CMakeModules/Findngspice.cmake

@@ -12,6 +12,15 @@ find_library( NGSPICE_LIBRARY ngspice
     PATH_SUFFIXES src/.libs lib
 )
 
+if( WIN32 AND MSYS )
+    # NGSPICE_LIBRARY points to libngspice.dll.a on Windows,
+    # but the goal is to find out the DLL name.
+    find_library( NGSPICE_DLL NAMES libngspice-0.dll libngspice-1.dll )
+else()
+    set( NGSPICE_DLL "${NGSPICE_LIBRARY}" )
+endif()
+
+
 include( FindPackageHandleStandardArgs )
 
 if( ${NGSPICE_INCLUDE_DIR} STREQUAL "NGSPICE_INCLUDE_DIR-NOTFOUND" OR ${NGSPICE_LIBRARY} STREQUAL "NGSPICE_LIBRARY-NOTFOUND" )
@@ -28,12 +37,10 @@ if( ${NGSPICE_INCLUDE_DIR} STREQUAL "NGSPICE_INCLUDE_DIR-NOTFOUND" OR ${NGSPICE_
 endif()
 
 find_package_handle_standard_args( ngspice
-  REQUIRED_VARS
+	REQUIRED_VARS NGSPICE_INCLUDE_DIR NGSPICE_LIBRARY NGSPICE_DLL )
-    NGSPICE_INCLUDE_DIR
-    NGSPICE_LIBRARY
-)
 
 mark_as_advanced(
     NGSPICE_INCLUDE_DIR
     NGSPICE_LIBRARY
+    NGSPICE_DLL
 )

eeschema/CMakeLists.txt

@@ -7,6 +7,15 @@ add_definitions( -DEESCHEMA )
 
 if( KICAD_SPICE )
     set( INC_AFTER ${INC_AFTER} ${NGSPICE_INCLUDE_DIR} )
+
+    # Find out the exact libngspice file name
+    get_filename_component( NGSPICE_DLL_REALPATH "${NGSPICE_DLL}" REALPATH )
+    get_filename_component( NGSPICE_DLL_FILE "${NGSPICE_DLL_REALPATH}" NAME )
+
+    set_property( SOURCE sim/ngspice.cpp
+        APPEND PROPERTY COMPILE_DEFINITIONS
+        NGSPICE_DLL_FILE="${NGSPICE_DLL_FILE}"
+        )
 endif()
 
 include_directories( BEFORE ${INC_BEFORE} )
@@ -315,6 +324,13 @@ target_link_libraries( eeschema_kiface
     ${wxWidgets_LIBRARIES}
     ${GDI_PLUS_LIBRARIES}
     )
+
+if( KICAD_SPICE )
+    target_link_libraries( eeschema_kiface
+        ${NGSPICE_LIBRARY}
+        )
+endif()
+
 set_target_properties( eeschema_kiface PROPERTIES
     # Decorate OUTPUT_NAME with PREFIX and SUFFIX, creating something like
     # _eeschema.so, _eeschema.dll, or _eeschema.kiface

eeschema/sim/ngspice.cpp

@@ -289,11 +289,11 @@ void NGSPICE::init_dll()
 // Extra effort to find libngspice
 #if defined(__WINDOWS__) || (__WXMAC__)
 #ifdef __WINDOWS__
-    wxFileName dllFile( "", "libngspice-0.dll" );
+    wxFileName dllFile( "", NGSPICE_DLL_FILE );
     const vector<string> dllPaths = { "", "/mingw64/bin", "/mingw32/bin" };
 #endif /* __WINDOWS__ */
 #ifdef __WXMAC__
-    wxFileName dllFile( "", "libngspice.0.dylib" );
+    wxFileName dllFile( "", NGSPICE_DLL_FILE );
     const vector<string> dllPaths = {
         GetOSXKicadUserDataDir() + "/PlugIns/ngspice",
         GetOSXKicadMachineDataDir() + "/PlugIns/ngspice",
@@ -320,7 +320,7 @@ void NGSPICE::init_dll()
     if( !m_dll.IsLoaded() ) // try also the system libraries
         m_dll.Load( wxDynamicLibrary::CanonicalizeName( "ngspice" ) );
 #else
-    m_dll.Load("libngspice.so.0");
+    m_dll.Load( NGSPICE_DLL_FILE );
 #endif /* __WINDOWS || __WXMAC__ */
 
     if( !m_dll.IsLoaded() )