Add missing standard library includes for self-sufficient headers

Fixes builds with newer GCC/libstdc++ that no longer provide <cstdint>,
<cstring>, <cfloat>, <memory>, <algorithm> etc. transitively. Also
disambiguates visit<> calls in taxonomy.h with the full namespace and
casts the character value in IfcCharacterDecoder to uint32_t to silence
ambiguous overload warnings.

src/ifcgeom/kernels/opencascade/IfcGeomTree.h

@@ -49,6 +49,7 @@
 #include <stack>
 #include <unordered_map>
 #include <unordered_set>
+#include <cstdint>
 #include <BRepExtrema_TriangleSet.hxx>
 #include <BRepLProp_SLProps.hxx>
 #include <BVH_BinaryTree.hxx>

src/ifcgeom/kernels/opencascade/clash_utils.cpp

@@ -1,5 +1,7 @@
 #include "clash_utils.h"
 #include <cassert>
+#include <cstdint>
+#include <cfloat>
 
 #define GU_CULLING_EPSILON_RAY_TRIANGLE FLT_EPSILON*FLT_EPSILON
 #define PX_MAX_F32 3.4028234663852885981170418348452e+38F

src/ifcgeom/mapping/mapping.h

@@ -8,6 +8,7 @@
 
 #include <mutex>
 #include <unordered_set>
+#include <cstdint>
 
 #define INCLUDE_SCHEMA(x) STRINGIFY(../../ifcparse/schemas/x.h)
 #include INCLUDE_SCHEMA(IfcSchema)

src/ifcgeom/taxonomy.h

@@ -17,6 +17,13 @@
 #include <tuple>
 #include <exception>
 #include <numeric>
+#include <cstdint>
+#include <cmath>
+#include <array>
+#include <limits>
+#include <functional>
+#include <algorithm>
+#include <stdexcept>
 
 #ifndef TAXONOMY_USE_UNIQUE_PTR
 #ifndef TAXONOMY_USE_NAKED_PTR
@@ -1623,25 +1630,25 @@ typedef item const* ptr;
 				// @todo Sad... now that we have templated collection members,
 				// we can't generally use collection_base anymore as a cast target.
 				if (auto s = taxonomy::dcast<taxonomy::collection>(i)) {
-					visit<taxonomy::collection>(s, fn);
+					ifcopenshell::geometry::visit<taxonomy::collection>(s, fn);
 				}
 				else if (auto s = taxonomy::dcast<taxonomy::loop>(i)) {
-					visit<taxonomy::loop>(s, fn);
+					ifcopenshell::geometry::visit<taxonomy::loop>(s, fn);
 				}
 				else if (auto s = taxonomy::dcast<taxonomy::face>(i)) {
-					visit<taxonomy::face>(s, fn);
+					ifcopenshell::geometry::visit<taxonomy::face>(s, fn);
 				}
 				else if (auto s = taxonomy::dcast<taxonomy::shell>(i)) {
-					visit<taxonomy::shell>(s, fn);
+					ifcopenshell::geometry::visit<taxonomy::shell>(s, fn);
 				}
 				else if (auto s = taxonomy::dcast<taxonomy::solid>(i)) {
-					visit<taxonomy::solid>(s, fn);
+					ifcopenshell::geometry::visit<taxonomy::solid>(s, fn);
 				}
 				else if (auto s = taxonomy::dcast<taxonomy::loft>(i)) {
-					visit<taxonomy::loft>(s, fn);
+					ifcopenshell::geometry::visit<taxonomy::loft>(s, fn);
 				}
 				else if (auto s = taxonomy::dcast<taxonomy::boolean_result>(i)) {
-					visit<taxonomy::boolean_result>(s, fn);
+					ifcopenshell::geometry::visit<taxonomy::boolean_result>(s, fn);
 				}
 				else {
 					fn(i);
@@ -1756,4 +1763,4 @@ typedef item const* ptr;
 
 }
 
-#endif
+#endif