let FLT_MAX be a string in definitions.lua to use after igGET_FLT_MAX to get compiler value

generator/generator.lua

@@ -78,6 +78,7 @@ local cimgui_overloads = {
 local cimgui_header = 
 [[//This file is automatically generated by generator.lua from https://github.com/cimgui/cimgui
 //based on imgui.h file version XXX from Dear ImGui https://github.com/ocornut/imgui]]
+local gdefines = {} --for FLT_MAX and others
 --------------------------------------------------------------------------
 --helper functions
 --------------------------------------------------------------------------
@@ -1203,6 +1204,50 @@ local function check_arg_detection(fdefs,typedefs)
 	end
 	print"-----------------end check arg detection-----------------------"
 end
+local function get_defines(t)
+	local pipe,err = io.popen([[gcc -E -dM -DIMGUI_DISABLE_OBSOLETE_FUNCTIONS -DIMGUI_API="" -DIMGUI_IMPL_API="" ../imgui/imgui.h]],"r")
+	local defines = {}
+	while true do
+		local line = pipe:read"*l"
+		if not line then break end
+		local key,value = line:match([[#define%s+(%S+)%s+(.+)]])
+		if not key or not value then 
+			--print(line)
+		else
+			defines[key]=value
+		end
+	end
+	pipe:close()
+	--require"anima.utils"
+	--prtable(defines)
+	--FLT_MAX
+	local ret = {}
+	for i,v in ipairs(t) do
+		local aa = defines[v]
+		while true do
+			local tmp = defines[aa]
+			if not tmp then 
+				break
+			else
+				aa = tmp
+			end
+		end
+		ret[v] = aa
+	end
+	return ret
+end
+--subtitution of FLT_MAX value for FLT_MAX 
+local function set_defines(fdefs)
+	for k,defT in pairs(fdefs) do
+		for i,def in ipairs(defT) do
+			for name,default in pairs(def.defaults) do
+				if default == gdefines.FLT_MAX then
+					def.defaults[name] = "FLT_MAX"
+				end
+			end
+		end
+	end
+end   
 --generate cimgui.cpp cimgui.h and auto versions depending on postfix
 local function cimgui_generation(postfix,STP,FP)
     --merge it in cimgui_template.h to cimgui.h
@@ -1247,6 +1292,11 @@ while true do
 end
 pipe:close()
 cimgui_header = cimgui_header:gsub("XXX",imgui_version)
+print("IMGUI_VERSION",imgui_version)
+--get some defines----------------------------
+if HAVE_GCC then
+	gdefines = get_defines{"IMGUI_VERSION","FLT_MAX"}
+end									
 --first without gcc
 ---[[
 print"------------------generation without precompiler------------------------"
@@ -1296,6 +1346,7 @@ check_arg_detection(pFP.defsT,typedefs_dict2)
 end
 
 ----------save fundefs in definitions.lua for using in bindings
+set_defines(pFP.defsT) 
 save_data("./output/definitions.lua",serializeTable("defs",pFP.defsT),"\nreturn defs")
 
 ----------save struct and enums lua table in structs_and_enums.lua for using in bindings