Make meson build work on windows.

By default, use more traditional linking pattern with meson.
The janet.exe will now link to janet-x.x.dll on windows (and
similar for linux/posix) when built with meson. This is slightly
less efficient and means that janet.exe built this way is no longer
standalone (you would need to move the dll along with the exe), but
plays better with most build systems.

build_win.bat

@@ -64,10 +64,6 @@ rc /nologo /fobuild\janet_win.res janet_win.rc
 %JANET_LINK% /out:janet.exe build\janet.obj build\shell.obj build\janet_win.res
 @if errorlevel 1 goto :BUILDFAIL
 
-@rem Build dynamic library (dlljanet.dll)
-%JANET_LINK% /DLL /out:build\dlljanet.dll build\janet.obj
-@if errorlevel 1 goto :BUILDFAIL
-
 @rem Build static library (libjanet.lib)
 %JANET_LINK_STATIC% /out:build\libjanet.lib build\janet.obj
 @if errorlevel 1 goto :BUILDFAIL
@@ -126,8 +122,6 @@ copy janet.def dist\janet.def
 janet.exe tools\patch-header.janet src\include\janet.h src\conf\janetconf.h build\janet.h
 copy build\janet.h dist\janet.h
 copy build\libjanet.lib dist\libjanet.lib
-copy build\dlljanet.dll dist\dlljanet.dll
-copy build\dlljanet.lib dist\dlljanet.lib
 
 @rem Create installer
 janet.exe -e "(->> janet/version (peg/match ''(* :d+ `.` :d+ `.` :d+)) first print)" > build\version.txt

meson.build

@@ -182,23 +182,30 @@ if not get_option('single_threaded')
   janet_dependencies += thread_dep
 endif
 
+if cc.has_argument('-fvisibility=hidden')
+  lib_cflags = ['-fvisibility=hidden']
+else
+  lib_cflags = []
+endif
 libjanet = library('janet', janetc,
   include_directories : incdir,
   dependencies : janet_dependencies,
   version: meson.project_version(),
   soversion: version_parts[0] + '.' + version_parts[1],
+  c_args : lib_cflags,
   install : true)
 
 # Extra c flags - adding -fvisibility=hidden matches the Makefile and
 # shaves off about 10k on linux x64, likely similar on other platforms.
 if cc.has_argument('-fvisibility=hidden')
-  extra_cflags = ['-fvisibility=hidden']
+  extra_cflags = ['-fvisibility=hidden', '-DJANET_DLL_IMPORT']
 else
-  extra_cflags = []
+  extra_cflags = ['-DJANET_DLL_IMPORT']
 endif
-janet_mainclient = executable('janet', janetc, mainclient_src,
+janet_mainclient = executable('janet', mainclient_src,
   include_directories : incdir,
   dependencies : janet_dependencies,
+  link_with: [libjanet],
   c_args : extra_cflags,
   install : true)
 

tools/msi/janet.wxs

@@ -132,12 +132,6 @@
             <Component Directory="CDir">
                 <File Source="dist\libjanet.lib"/>
             </Component>
-            <Component Directory="CDir">
-                <File Source="dist\dlljanet.dll"/>
-            </Component>
-            <Component Directory="CDir">
-                <File Source="dist\dlljanet.lib"/>
-            </Component>
 
             <Component Id="LibraryComponent" Directory="LibraryDir" Guid="3860e981-5f94-4002-b5d5-2d9ec0d2792d" KeyPath="yes">
                 <RemoveFolder Id="RemoveLibraryDir" On="uninstall" />