Here's what I get with Apple LLVM version 10.0.1 (clang-1001.0.43.3) for x86_64-apple-darwin18.5.0:

Produced by enquire version 5.1a, CWI, Amsterdam
http://www.cwi.nl/~steven/enquire.html
Compiler claims to be ANSI C level 1

Compiler names are at least 64 chars long
Preprocessor names are at least 64 long

SIZES
char = 8 bits, signed
short=16 int=32 long=64 float=32 double=64 bits
long double=128 bits
char*=64 bits BEWARE! larger than int!
int* =64 bits BEWARE! larger than int!
func*=64 bits BEWARE! larger than int!
Type size_t is unsigned long
Type wchar_t is signed int

ALIGNMENTS
char=1 short=2 int=4 long=8
float=4 double=8
long double=16
char*=8 int*=8 func*=8

CHARACTER ORDER
short: BA
int: DCBA
long: HGFEDCBA

PROPERTIES OF POINTERS
Char and int pointer formats seem identical
Char and function pointer formats seem identical
Strings are shared
Type ptrdiff_t is signed long
Dereferencing NULL causes a trap

PROPERTIES OF INTEGRAL TYPES
Overflow of a short does not generate a trap
Maximum short = 32767 (= 2**15-1)
Minimum short = -32768
Overflow of an int does not generate a trap
Maximum int = 2147483647 (= 2**31-1)
Minimum int = -2147483648
Overflow of a long does not generate a trap
Maximum long = 9223372036854775807 (= 2**63-1)
Minimum long = -9223372036854775808
Maximum unsigned short = 65535
Maximum unsigned int = 4294967295
Maximum unsigned long = 18446744073709551615

PROMOTIONS
unsigned short promotes to signed int
long+unsigned gives signed long

PROPERTIES OF FLOAT
Base = 2
Significant base digits = 24 (= at least 6 decimal digits)
Arithmetic rounds towards nearest
Tie breaking rounds to even
Smallest x such that 1.0-base**x != 1.0 = -24
Smallest x such that 1.0-x != 1.0 = 2.98023259e-08
Smallest x such that 1.0+base**x != 1.0 = -23
Smallest x such that 1.0+x != 1.0 = 5.96046519e-08
(Above number + 1.0) - 1.0 = 1.19209290e-07
Number of bits used for exponent = 8
Minimum normalised exponent = -126
Minimum normalised positive number = 1.17549435e-38
The smallest numbers are not kept normalised
Smallest unnormalised positive number = 1.40129846e-45
Maximum exponent = 128
Maximum number = 3.40282347e+38
Overflow doesn't seem to generate a trap
There is an 'infinite' value
Divide by zero doesn't generate a trap
Arithmetic uses a hidden bit
It looks like single length IEEE format

PROPERTIES OF DOUBLE
Base = 2
Significant base digits = 53 (= at least 15 decimal digits)
Arithmetic rounds towards nearest
Tie breaking rounds to even
Smallest x such that 1.0-base**x != 1.0 = -53
Smallest x such that 1.0-x != 1.0 = 5.5511151231257839e-17
Smallest x such that 1.0+base**x != 1.0 = -52
Smallest x such that 1.0+x != 1.0 = 1.1102230246251568e-16
(Above number + 1.0) - 1.0 = 2.2204460492503131e-16
Number of bits used for exponent = 11
Minimum normalised exponent = -1022
Minimum normalised positive number = 2.2250738585072014e-308
The smallest numbers are not kept normalised
Smallest unnormalised positive number = 4.9406564584124654e-324
Maximum exponent = 1024
Maximum number = 1.7976931348623157e+308
Overflow doesn't seem to generate a trap
There is an 'infinite' value
Divide by zero doesn't generate a trap
Arithmetic uses a hidden bit
It looks like double length IEEE format

PROPERTIES OF LONG DOUBLE
Base = 2
Significant base digits = 64 (= at least 18 decimal digits)
Arithmetic rounds towards nearest
Tie breaking rounds to even
Smallest x such that 1.0-base**x != 1.0 = -64
Smallest x such that 1.0-x != 1.0 = 2.71050543121376108531e-20
Smallest x such that 1.0+base**x != 1.0 = -63
Smallest x such that 1.0+x != 1.0 = 5.42101086242752217063e-20
(Above number + 1.0) - 1.0 = 1.08420217248550443401e-19
Number of bits used for exponent = 15
Minimum normalised exponent = -16382
Minimum normalised positive number = 3.36210314311209350626e-4932
The smallest numbers are not kept normalised
Smallest unnormalised positive number = 3.64519953188247460253e-4951
Maximum exponent = 16384
Maximum number = 1.18973149535723176502e+4932
Overflow doesn't seem to generate a trap
There is an 'infinite' value
Divide by zero doesn't generate a trap
Only 79 of the 128 bits of a long double are actually used
It doesn't look like IEEE format

Float expressions are evaluated in float precision
Double expressions are evaluated in double precision
Long double expressions are evaluated in long double precision
Memory mallocatable ~= 138 Tbytes