Replace atof usages with strtod (str_tofloat wrapper)

As `atof` does not provide any way to detect errors and can cause undefined behavior on errors, i.e. when the result cannot be represented as a `float`.

References:

- https://wiki.sei.cmu.edu/confluence/display/c/ERR07-C.+Prefer+functions+that+support+error+checking+over+equivalent+functions+that+don%27t
- https://pubs.opengroup.org/onlinepubs/9699919799/functions/atof.html

src/base/system.cpp

@@ -3402,7 +3402,7 @@ int str_isallnum(const char *str)
 int str_toint(const char *str) { return str_toint_base(str, 10); }
 int str_toint_base(const char *str, int base) { return strtol(str, NULL, base); }
 unsigned long str_toulong_base(const char *str, int base) { return strtoul(str, NULL, base); }
-float str_tofloat(const char *str) { return atof(str); }
+float str_tofloat(const char *str) { return strtod(str, NULL); }
 
 int str_utf8_comp_nocase(const char *a, const char *b)
 {

src/tools/map_replace_area.cpp

@@ -80,10 +80,10 @@ int main(int argc, const char *argv[])
 
 	for(int i = 0; i < 2; i++)
 	{
-		aaaGameAreas[i][0][0] = atof(argv[2 + i * 3]) * 32; //x
-		aaaGameAreas[i][1][0] = atof(argv[3 + i * 3]) * 32; //y
-		aaaGameAreas[i][0][1] = aaaGameAreas[i][0][0] + atof(argv[7]) * 32; //x + width
-		aaaGameAreas[i][1][1] = aaaGameAreas[i][1][0] + atof(argv[8]) * 32; //y + height
+		aaaGameAreas[i][0][0] = str_tofloat(argv[2 + i * 3]) * 32; //x
+		aaaGameAreas[i][1][0] = str_tofloat(argv[3 + i * 3]) * 32; //y
+		aaaGameAreas[i][0][1] = aaaGameAreas[i][0][0] + str_tofloat(argv[7]) * 32; //x + width
+		aaaGameAreas[i][1][1] = aaaGameAreas[i][1][0] + str_tofloat(argv[8]) * 32; //y + height
 	}
 
 	cmdline_free(argc, argv);