diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 155ea6273..cfa5c8d39 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -225,6 +225,7 @@ jobs:
         -  { os: ubuntu-latest, name: 'Heap Test',      opt: '--enable-debugheap  --enable-verifyheap --enable-werror' }
         -  { os: ubuntu-latest, name: 'Thin Build',     opt: '--enable-thin --enable-werror' }
         -  { os: ubuntu-latest, name: 'Dev Mode',       opt: '--enable-devmode' }
+        -  { os: ubuntu-latest, name: 'Rng Libraries',  opt: '--enable-rnglibs' }
     steps:
     - name: Checkout
       uses: actions/checkout@v4
diff --git a/src/h/cpuconf.h b/src/h/cpuconf.h
index 53605cf08..beeabf4c1 100644
--- a/src/h/cpuconf.h
+++ b/src/h/cpuconf.h
@@ -55,12 +55,12 @@
 
    #ifndef F_Typecode
       #define F_Typecode  0x2000000000000000    /* set if dword incls typecode*/
-   #endif               /* F_Typecode */
+   #endif                               /* F_Typecode */
 
    #ifdef RngLibrary
       #define F_RngState  0x0800000000000000 /* set if RNG state */
-   #endif               /* RngLibrary */
-#endif                  /* WordBits == 64 */
+   #endif                               /* RngLibrary */
+#endif                                  /* WordBits == 64 */
 
 /*
  * 32-bit words.
@@ -73,15 +73,15 @@
 
    #define MaxNegInt "-2147483648"
 
-   #define MaxStrLen 0777777777     /* maximum string length */
+   #define MaxStrLen     0777777777     /* maximum string length */
 
-   #define F_Nqual  0x80000000  /* set if NOT string qualifier */
-   #define F_Var    0x40000000  /* set if variable */
-   #define F_Ptr    0x10000000  /* set if value field is pointer */
-   #define F_Typecode   0x20000000  /* set if dword includes type code */
+   #define F_Nqual      0x80000000      /* set if NOT string qualifier */
+   #define F_Var        0x40000000      /* set if variable */
+   #define F_Ptr        0x10000000      /* set if value field is pointer */
+   #define F_Typecode   0x20000000      /* set if dword includes type code */
 #ifdef RngLibrary
-   #define F_RngState   0x08000000 /* set if RNG state */
-#endif                  /*RngLibrary */
+   #define F_RngState   0x08000000     /* set if RNG state */
+#endif                                 /*RngLibrary */
 
    #define MaxNegInt "-2147483648"
 
@@ -134,7 +134,7 @@
    #define MaxInt       077777                  /* largest int */
 
    #ifndef MaxListSlots
-      #define MaxListSlots 8000         /* largest list-element block */
+      #define MaxListSlots 8000                 /* largest list-element block */
    #endif                               /* MaxListSlots */
 
    /*
diff --git a/src/runtime/data.r b/src/runtime/data.r
index accc01a8d..edde7fc58 100644
--- a/src/runtime/data.r
+++ b/src/runtime/data.r
@@ -271,8 +271,6 @@ struct descrip rngIconName;
 struct b_cons *rngLibs;         /* chain of loaded libraries */
 #endif                                  /* RngLibrary */
 
-
-
 /*
  * Run-time error numbers and text.
  */
@@ -424,12 +422,12 @@ struct errtab errtab[] = {
     * for anything else. If any RNG wants more than 5 error messages,
     * add some more boilerplate messages to the above.
     */
-   
+
    750, "Library not loaded",
    751, "Function not found in PRNG library",
    752, "startRng() failed",
 
-#endif					/* RngLibrary */
+#endif                                  /* RngLibrary */
 
 #ifdef PosixFns
    1040, "socket error",
diff --git a/src/runtime/fmisc.r b/src/runtime/fmisc.r
index 88c3ac9c3..c738b4e1d 100644
--- a/src/runtime/fmisc.r
+++ b/src/runtime/fmisc.r
@@ -2706,13 +2706,14 @@ function{0,1} rngbits(n)
            if (n == 0 ) n = curtstate->rng->info.property.blockBits;
 
            elems = (((n+7)/8 + sizeof(word) - 1)/sizeof(word));
-           Protect(ap = (struct b_intarray *) alcintarray(elems), runerr(0));
+           reserve(Blocks, sizeof(struct b_list) + sizeof(struct b_intarray) + (elems - 1)* sizeof(word));
+           Protect(ap = (struct b_intarray *) alcintarray(elems), runerr(307));
            if (0 > curtstate->rng->info.api.getRandomBits(n, &(ap->a[0]))) {
              fail;
            }
 
            result.dword = D_List;
-           result.vword.bptr = (union block *)alclisthdr(elems, (union block *) ap);
+           Protect(result.vword.bptr = (union block *)alclisthdr(elems, (union block *) ap),runerr(307));
            return result;
          }
        }
@@ -2760,7 +2761,7 @@ function{0,1} rngbitstring(n)
 
            if ( 0 < curtstate->rng->info.api.getRandomBits(n, bitbuff)) {
              /* Allocate a string of the required size for the answer */
-             Protect(StrLoc(result) = alcstr(NULL, n), runerr(0));
+             Protect(StrLoc(result) = alcstr(NULL, n), runerr(306));
            
              /* Populate result with '0' and '1' characters.
               * The bits are in the natural left to right reading order,
diff --git a/src/runtime/oasgn.r b/src/runtime/oasgn.r
index e9e909e0c..a32fac84a 100644
--- a/src/runtime/oasgn.r
+++ b/src/runtime/oasgn.r
@@ -15,7 +15,7 @@ int rngAsgnState(struct threadstate *ts, struct descrip v)
    * if v is an intArray and the first element is the RNG id and the size
    * is right, assign the rest of the array to the Rng State, otherwise refuse.
    */
-  if ((Type(v) == T_List) &&
+  if ((is:list(v)) &&
       (v.vword.bptr->List.size == elems) &&
       (v.vword.bptr->List.listhead->Intarray.title == T_Intarray) &&
       (v.vword.bptr->List.listhead->Intarray.a[0] == ts->rng->info.id))