Replace CL_REQUIRE/CL_PROVIDE(cl_LF_globals) with portable code.

The order of initialization of non-local objects in different compilation units
is not specified in C++. Hence special care should be taken to avoid static
initialization order fiasco. CLN solved the problem with some evil (GCC
specific, and even GCC-version-specific) hack. Replace it with a technique
similar to one used in STL to initialize std::cout and friends.

include/cln/lfloat_class.h

@@ -53,7 +53,14 @@ inline cl_LF::operator struct cl_heap_lfloat * () const
 extern const cl_LF cl_LF_0;
 inline cl_LF::cl_LF ()
 	: cl_F ((cl_private_thing) (struct cl_heap_lfloat *) cl_LF_0) {}
-CL_REQUIRE(cl_LF_globals)
+class cl_LF_globals_init_helper
+{
+	static int count;
+public:
+	cl_LF_globals_init_helper();
+	~cl_LF_globals_init_helper();
+};
+static cl_LF_globals_init_helper cl_LF_globals_init_helper_instance;
 #if 0 // see cl_LF_impl.h
 inline cl_LF::cl_LF (struct cl_heap_lfloat * ptr)
 	: cl_F ((cl_private_thing) ptr) {}

src/float/lfloat/elem/cl_LF_globals.cc

@@ -3,8 +3,6 @@
 // General includes.
 #include "cl_sysdep.h"
 
-CL_PROVIDE(cl_LF_globals)
-
 // Specification.
 #include "cln/number.h"
 
@@ -17,8 +15,21 @@ CL_PROVIDE(cl_LF_globals)
 namespace cln {
 
 // Only needed for the default constructor of cl_LF.
-const cl_LF cl_LF_0 = encode_LF0(LF_minlen); // 0.0L0
+const cl_LF cl_LF_0 = cl_LF_0; // 0.0L0
+
+int cl_LF_globals_init_helper::count = 0;
+cl_LF_globals_init_helper::cl_LF_globals_init_helper()
+{
+	if (count++ == 0)
+		new ((void *)&cl_LF_0) cl_LF(encode_LF0(LF_minlen)); // 0.0L0
+}
+
+cl_LF_globals_init_helper::~cl_LF_globals_init_helper()
+{
+	if (--count == 0) {
+		// Nothing to clean up
+	}
+}
 
 }  // namespace cln
 
-CL_PROVIDE_END(cl_LF_globals)