[NDK][NTOS] Add global definition of INIT_FUNCTION/INIT_SECTION (#779)

* Add an NDK header to define INIT_FUNCTION/INIT_SECTION globally
* Use _declspec(allocate(x)) and _declspec(code_seg(x)) on MSVC versions that support it
* Use INIT_FUNCTION on functions only and INIT_SECTION on data only (required by MSVC)
* Place INIT_FUNCTION before the return type (required by MSVC)
* Make sure declarations and implementations share the same modifiers (required by MSVC)
* Add a global linker option to suppress warnings about defined but unused INIT section
* Merge INIT section into .text in freeldr

sdk/include/ndk/halfuncs.h

@@ -25,6 +25,7 @@ Author:
 #include <umtypes.h>
 #include <haltypes.h>
 #include <ketypes.h>
+#include <section_attribs.h>
 
 #ifndef NTOS_MODE_USER
 
@@ -80,6 +81,7 @@ HalInitializeProcessor(
     _In_ struct _LOADER_PARAMETER_BLOCK *LoaderBlock
 );
 
+INIT_FUNCTION
 NTHALAPI
 BOOLEAN
 NTAPI
@@ -175,6 +177,7 @@ HalGetInterruptSource(
 );
 #endif
 
+INIT_FUNCTION
 NTHALAPI
 VOID
 NTAPI