Compiler fixes for gcc 10

This patch fixes a few compile warnings/errors that now occur when using gcc
10+.

Also, the Makefile.rules check to turn off partial inlining in gcc versions
greater or equal to 8.2.1 had a bug where it only it only checked against
versions with at least 3 numbers (ex: 8.2.1 vs 10). This patch now ensures
any version above the specified version is correctly compared.

Change-Id: I54718496eb0c3ce5bd6d427cd279a29e8d2825f9

addons/ooh323c/src/decode.c

@@ -737,6 +737,10 @@ static int decodeOctets
          nbits -= 8;
       }
 
+      if (nbits <= 0) {
+         return ASN_OK;
+      }
+
       /* Copy last partial byte */
 
       if (nbits >= rshift) {
@@ -752,7 +756,7 @@ static int decodeOctets
 
          pctxt->buffer.bitOffset = 8 - nbitsInLastOctet;
       }
-      else if (nbits > 0) {  /* nbits < rshift */
+      else {  /* nbits > 0 && nbits < rshift */
          pbuffer[i] =
             pctxt->buffer.data[pctxt->buffer.byteIndex] << lshift;
          pctxt->buffer.bitOffset = rshift - nbits;
@@ -832,8 +836,8 @@ int decodeOpenType
 
 int decodeSemiConsInteger (OOCTXT* pctxt, ASN1INT* pvalue, ASN1INT lower)
 {
-   signed char b;
-   unsigned char ub;
+   signed char b = 0;
+   unsigned char ub = 0;
    ASN1UINT nbytes;
    int stat;