With these changes I was able to compile steghide 0.5.1.

steghide.patch

--- ../steghide-0.5.1 2/./src/AuSampleValues.cc  2003-09-28 18:30:30.000000000 +0300
+++ ./src/AuSampleValues.cc     2021-03-28 05:22:48.000000000 +0300
@@ -21,17 +21,17 @@
 #include "AuSampleValues.h"
 
 // AuMuLawSampleValue
-const BYTE AuMuLawSampleValue::MinValue = 0 ;
-const BYTE AuMuLawSampleValue::MaxValue = BYTE_MAX ;
+template<> const BYTE AuMuLawSampleValue::MinValue = 0 ;
+template<> const BYTE AuMuLawSampleValue::MaxValue = BYTE_MAX ;
 
 // AuPCM8SampleValue
-const SBYTE AuPCM8SampleValue::MinValue = SBYTE_MIN ;
-const SBYTE AuPCM8SampleValue::MaxValue = SBYTE_MAX ;
+template<> const SBYTE AuPCM8SampleValue::MinValue = SBYTE_MIN ;
+template<> const SBYTE AuPCM8SampleValue::MaxValue = SBYTE_MAX ;
 
 // AuPCM16SampleValue
-const SWORD16 AuPCM16SampleValue::MinValue = SWORD16_MIN ;
-const SWORD16 AuPCM16SampleValue::MaxValue = SWORD16_MAX ;
+template<> const SWORD16 AuPCM16SampleValue::MinValue = SWORD16_MIN ;
+template<> const SWORD16 AuPCM16SampleValue::MaxValue = SWORD16_MAX ;
 
 // AuPCM32SampleValue
-const SWORD32 AuPCM32SampleValue::MinValue = SWORD32_MIN ;
-const SWORD32 AuPCM32SampleValue::MaxValue = SWORD32_MAX ;
+template<> const SWORD32 AuPCM32SampleValue::MinValue = SWORD32_MIN ;
+template<> const SWORD32 AuPCM32SampleValue::MaxValue = SWORD32_MAX ;
--- ../steghide-0.5.1 2/./src/MHashPP.cc        2003-10-05 13:17:50.000000000 +0300
+++ ./src/MHashPP.cc    2021-03-28 05:24:01.000000000 +0300
@@ -120,7 +120,7 @@
 
 std::string MHashPP::getAlgorithmName (hashid id)
 {
-       char *name = mhash_get_hash_name (id) ;
+       char *name = reinterpret_cast<char *>(mhash_get_hash_name (id)) ;
        std::string retval ;
        if (name == NULL) {
                retval = std::string ("<algorithm not found>") ;