Use compiler built-in macros to determine if argument parsing can use double or float for FLOAT arguments. (I.E. whether double fits in a long's memory.) Check in a way that the macros not being defined just gives us the shorter one.
diff --git a/lib/pending.h b/lib/pending.h
index 67605c0..5e3b309 100644
--- a/lib/pending.h
+++ b/lib/pending.h
@@ -1,13 +1,5 @@
// pending.h - header for pending.c
-// Unfortunately, sizeof() doesn't work in a preprocessor test. TODO.
-
-//#if sizeof(double) <= sizeof(long)
-//typedef double FLOAT;
-//#else
-typedef float FLOAT;
-//#endif
-
// password.c
#define MAX_SALT_LEN 20 //3 for id, 16 for key, 1 for '\0'
#define SYS_FIRST_ID 100
diff --git a/lib/portability.h b/lib/portability.h
index 099f321..1d540ac 100644
--- a/lib/portability.h
+++ b/lib/portability.h
@@ -148,7 +148,8 @@
#define SWAP_LE64(x) (x)
#endif
-#if defined(__APPLE__) || defined(__ANDROID__) || (defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 10)
+#if defined(__APPLE__) || defined(__ANDROID__) \
+ || (defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 10)
ssize_t getdelim(char **lineptr, size_t *n, int delim, FILE *stream);
ssize_t getline(char **lineptr, size_t *n, FILE *stream);
#endif
@@ -163,3 +164,11 @@
#ifndef O_NOFOLLOW
#define O_NOFOLLOW 0
#endif
+
+#if defined(__SIZEOF_DOUBLE__) && defined(__SIZEOF_LONG__) \
+ && __SIZEOF_DOUBLE__ <= __SIZEOF_LONG__
+typedef double FLOAT;
+#else
+typedef float FLOAT;
+#endif
+