--- spack-src/src/sequences.c.org	2020-03-05 13:34:15.764971874 +0900
+++ spack-src/src/sequences.c	2020-03-05 13:49:45.315370741 +0900
@@ -2180,7 +2180,7 @@
 
 	ch = skip_seq_whitespace (_seq);
 
-	if (ch != '>') seq_ungetc (ch, _seq);
+	if (ch != '>') seq_ungetc ((char)ch, _seq);
 	          else parse_fasta_header (_seq);
 
 	debugFastaFile_2;
@@ -2298,7 +2298,7 @@
 	if (ch == '\r') // handle possible DOS CR-LF line ending
 		{
 		ch = seq_getc (_seq);
-		if (ch != '\n') seq_ungetc (ch, _seq);
+		if (ch != '\n') seq_ungetc ((char)ch, _seq);
 		}
 
 	}
@@ -2346,7 +2346,7 @@
 	while (ch != EOF)
 		{
 		if ((prevCh == '\n') && (ch == '>')) // (start of next sequence)
-			{ seq_ungetc (ch, _seq);  break; }
+			{ seq_ungetc ((char)ch, _seq);  break; }
 
 		if ((_seq->separatorCh == 0) || (ch != _seq->separatorCh))
 			{
@@ -2445,7 +2445,7 @@
 //		while (ch != EOF)
 //			{
 //			if ((prevCh == '\n') && (ch == '>')) // (start of next sequence)
-//				{ seq_ungetc (ch, _seq);  break; }
+//				{ seq_ungetc ((char)ch, _seq);  break; }
 //
 //			switch (char_to_fasta_type[(u8)ch])
 //				{
@@ -2627,7 +2627,7 @@
 	if (ch == '\r') // handle possible DOS CR-LF line ending
 		{
 		ch = seq_getc (_seq);
-		if (ch != '\n') seq_ungetc (ch, _seq);
+		if (ch != '\n') seq_ungetc ((char)ch, _seq);
 		}
 
 	// copy from trueHeader into the header (unless the header is locked), then
@@ -2762,7 +2762,7 @@
 	if (ch == '\r') // handle possible DOS CR-LF line ending
 		{
 		ch = seq_getc (_seq);
-		if (ch != '\n') seq_ungetc (ch, _seq);
+		if (ch != '\n') seq_ungetc ((char)ch, _seq);
 		}
 
 	_seq->v[_seq->len] = 0;				// (set the terminating zero)
@@ -2834,7 +2834,7 @@
 	if (ch == '\r') // handle possible DOS CR-LF line ending
 		{
 		ch = seq_getc (_seq);
-		if (ch != '\n') seq_ungetc (ch, _seq);
+		if (ch != '\n') seq_ungetc ((char)ch, _seq);
 		}
 
 	//////////
@@ -2877,7 +2877,7 @@
 	if (ch == '\r') // handle possible DOS CR-LF line ending
 		{
 		ch = seq_getc (_seq);
-		if (ch != '\n') seq_ungetc (ch, _seq);
+		if (ch != '\n') seq_ungetc ((char)ch, _seq);
 		}
 
 	if (qualCount < nucCount) goto not_enough_qualities;
@@ -3061,7 +3061,7 @@
 			ch = seq_getc (_seq);
 		}
 
-	if (ch != '>') seq_ungetc (ch, _seq);
+	if (ch != '>') seq_ungetc ((char)ch, _seq);
 	          else parse_csfasta_header (_seq);
 
 	//////////
@@ -3166,7 +3166,7 @@
 	if (ch == '\r') // handle possible DOS CR-LF line ending
 		{
 		ch = seq_getc (_seq);
-		if (ch != '\n') seq_ungetc (ch, _seq);
+		if (ch != '\n') seq_ungetc ((char)ch, _seq);
 		}
 
 	}
@@ -3223,7 +3223,7 @@
 		{
 		if ((prevCh == '\n')
 		 && ((ch == '#') || (ch == '>'))) 			// (start of next sequence)
-			{ seq_ungetc (ch, _seq);  break; }
+			{ seq_ungetc ((char)ch, _seq);  break; }
 
 		chType = char_to_csfasta_type[(u8)ch];
 		switch (chType)
@@ -3324,7 +3324,7 @@
 //			{
 //			if ((prevCh == '\n')
 //			 && ((ch == '#') || (ch == '>')))		// (start of next sequence)
-//				{ seq_ungetc (ch, _seq);  break; }
+//				{ seq_ungetc ((char)ch, _seq);  break; }
 //
 //			switch (char_to_csfasta_type[(u8)ch])
 //				{
@@ -4701,10 +4701,10 @@
 	else if (magic == oldQdnaMagicBig)    { oldFormat = bigEndian = true; }
 	else
 		{
-		seq_ungetc ((magic >> 24) & 0xFF, _seq);
-		seq_ungetc ((magic >> 16) & 0xFF, _seq);
-		seq_ungetc ((magic >> 8)  & 0xFF, _seq);
-		seq_ungetc ( magic        & 0xFF, _seq);
+		seq_ungetc ((char) ((magic >> 24) & 0xFF), _seq);
+		seq_ungetc ((char) ((magic >> 16) & 0xFF), _seq);
+		seq_ungetc ((char) ((magic >> 8)  & 0xFF), _seq);
+		seq_ungetc ((char) ( magic        & 0xFF), _seq);
 		oldFormat = true;
 		}
 
@@ -5050,7 +5050,7 @@
 	                  _seq->filename);
 	if (ch == EOF) return false;			// we're at end of file now
 
-	seq_ungetc (ch, _seq);					// save what we peeked at
+	seq_ungetc ((char)ch, _seq);			// save what we peeked at
 	return true;							// we have characters to process
 	}
 
@@ -5074,7 +5074,8 @@
 	int		headerLen;
 	int		mustBeHeader;
 	int		leadingWhite;
-	char	ch, *s;
+	int		ch;
+	char*	s;
 	int		ix;
 
 	debugNamesFile_12;
@@ -5118,7 +5119,7 @@
 
 		ch = seq_getc (_seq);
 		if (ch == EOF) goto failure;
-		while ((ch != '\n') && (isspace (ch)))
+		while ((ch != '\n') && (isspace (ch)))  // nota bene: isspace's arg type is an int
 			{
 			leadingWhite++;
 			ch = seq_getc (_seq);
@@ -5186,7 +5187,7 @@
 
 	// unget the header
 
-	seq_ungetc (ch, _seq);	// (ch terminated the header)
+	seq_ungetc ((char)ch, _seq);	// (ch terminated the header)
 
 	for (ix=strlen(buffer) ; ix>0 ; )
 		seq_ungetc (buffer[--ix], _seq);
@@ -5218,7 +5219,8 @@
 	char	buffer[maxSequenceHeader+1];
 	char*	header;
 	int		headerLen;
-	char	ch, *s;
+	int		ch;
+	char*	s;
 	int		ix;
 	int		ok;
 
@@ -5257,7 +5259,7 @@
 		if (ch == '\r') // handle possible DOS CR-LF line ending
 			{
 			ch = seq_getc (_seq);
-			if (ch != '\n') seq_ungetc (ch, _seq);
+			if (ch != '\n') seq_ungetc ((char)ch, _seq);
 			}
 
 		// if we have a name trigger, locate the sequence's name
@@ -5310,7 +5312,7 @@
 
 	// unget the header
 
-	seq_ungetc (ch, _seq);	// (ch terminated the header)
+	seq_ungetc ((char)ch, _seq);	// (ch terminated the header)
 
 	for (ix=strlen(buffer) ; ix>0 ; )
 		seq_ungetc (buffer[--ix], _seq);
@@ -9067,10 +9069,10 @@
 
 	// put those four bytes back in the file (in reverse of the read order)
 
-	seq_ungetc (magic >> 24, _seq);
-	seq_ungetc (magic >> 16, _seq);
-	seq_ungetc (magic >>  8, _seq);
-	seq_ungetc (magic      , _seq);
+	seq_ungetc ((char) (magic >> 24), _seq);
+	seq_ungetc ((char) (magic >> 16), _seq);
+	seq_ungetc ((char) (magic >>  8), _seq);
+	seq_ungetc ((char)  magic       , _seq);
 
 	if (type != seq_type_unknown)
 		return type;
@@ -9080,7 +9082,7 @@
 	//////////
 
 	ch = seq_getc (_seq);
-	seq_ungetc (ch, _seq);
+	seq_ungetc ((char)ch, _seq);
 	if (ch == '@')
 		return seq_type_fastq;
 
@@ -9095,12 +9097,12 @@
 	ch = seq_getc (_seq);
 	if (ch == '#')
 		{
-		seq_ungetc (ch, _seq);
+		seq_ungetc ((char)ch, _seq);
 		return seq_type_csfasta;
 		}
 
 	if (ch != '>')
-		seq_ungetc (ch, _seq);
+		seq_ungetc ((char)ch, _seq);
 	else
 		{
 		// read header
@@ -9122,12 +9124,12 @@
 
 		intCh = seq_getc (_seq);
 		if (intCh == EOF) goto unknown;
-		buffer[bufferLen++] = intCh;
+		buffer[bufferLen++] = (char) intCh;
 		if (ustrchr ("ACGTacgtNn", intCh) != NULL)
 			{
 			intCh = seq_getc (_seq);
 			if (intCh == EOF) goto unknown;
-			buffer[bufferLen++] = intCh;
+			buffer[bufferLen++] = (char) intCh;
 			if (ustrchr ("ACGTacgtNn", intCh) != NULL)
 				type = seq_type_fasta;
 			else if (ustrchr ("0123", intCh) != NULL)