diff --git a/dub.sdl b/dub.sdl
index 8ed5d4e..00b1dfc 100644
--- a/dub.sdl
+++ b/dub.sdl
@@ -4,3 +4,10 @@ authors "Team Phobos"
 copyright "Copyright © 2017, Team Phobos"
 license "BSL-1.0"
 dependency "mir-core" version=">=0.0.5 <0.3.0"
+
+configuration "unittest" {
+}
+
+configuration "wasm" {
+	dflags "-mtriple=wasm32-unknown-unknown-wasm" "-betterC"
+}
diff --git a/source/stdx/allocator/building_blocks/bitmapped_block.d b/source/stdx/allocator/building_blocks/bitmapped_block.d
index 81d8841..b67f55c 100644
--- a/source/stdx/allocator/building_blocks/bitmapped_block.d
+++ b/source/stdx/allocator/building_blocks/bitmapped_block.d
@@ -57,7 +57,14 @@ struct BitmappedBlock(size_t theBlockSize, uint theAlignment = platformAlignment
         auto m = cast(ubyte[])(AlignedMallocator.instance.alignedAllocate(1024 * 64,
                                 max(theAlignment, cast(uint) size_t.sizeof)));
         scope(exit) AlignedMallocator.instance.deallocate(m);
-        testAllocator!(() => BitmappedBlock(m));
+        static if (theBlockSize == chooseAtRuntime)
+        {
+            testAllocator!(() => BitmappedBlock!(theBlockSize, theAlignment, NullAllocator)(m, 64));
+        }
+        else
+        {
+            testAllocator!(() => BitmappedBlock!(theBlockSize, theAlignment, NullAllocator)(m));
+        }
     }
     static assert(theBlockSize > 0 && theAlignment.isGoodStaticAlignment);
     static assert(theBlockSize == chooseAtRuntime
@@ -81,7 +88,7 @@ struct BitmappedBlock(size_t theBlockSize, uint theAlignment = platformAlignment
         @property uint blockSize() { return _blockSize; }
         @property void blockSize(uint s)
         {
-            assert(!_control && s % alignment == 0);
+            assert(_control.allAre0() && s % alignment == 0);
             _blockSize = s;
         }
         private uint _blockSize;
@@ -193,6 +200,13 @@ struct BitmappedBlock(size_t theBlockSize, uint theAlignment = platformAlignment
         assert(_blocks * blockSize >= capacity);
     }
 
+    static if (chooseAtRuntime == theBlockSize)
+    this(ubyte[] data, uint blockSize)
+    {
+        this._blockSize = blockSize;
+        this(data);
+    }
+
     /**
     If $(D ParentAllocator) is not $(D NullAllocator) and defines $(D
     deallocate), the destructor is defined to deallocate the block held.
diff --git a/source/stdx/allocator/building_blocks/region.d b/source/stdx/allocator/building_blocks/region.d
index c25ff62..43d6c71 100644
--- a/source/stdx/allocator/building_blocks/region.d
+++ b/source/stdx/allocator/building_blocks/region.d
@@ -390,6 +390,7 @@ struct InSituRegion(size_t size, size_t minAlign = platformAlignment)
     else version (MIPS64) enum growDownwards = Yes.growDownwards;
     else version (SPARC) enum growDownwards = Yes.growDownwards;
     else version (SystemZ) enum growDownwards = Yes.growDownwards;
+    else version (WebAssembly) enum growDownwards = Yes.growDownwards;
     else static assert(0, "Dunno how the stack grows on this architecture.");
 
     @disable this(this);
diff --git a/source/stdx/allocator/building_blocks/segregator.d b/source/stdx/allocator/building_blocks/segregator.d
index 361f3bf..830c7a1 100644
--- a/source/stdx/allocator/building_blocks/segregator.d
+++ b/source/stdx/allocator/building_blocks/segregator.d
@@ -247,7 +247,7 @@ struct Segregator(size_t threshold, SmallAllocator, LargeAllocator)
                 && __traits(hasMember, LargeAllocator, "empty"))
         Ternary empty()
         {
-            return _small.empty && _large.empty;
+            return _small.empty & _large.empty;
         }
 
         static if (__traits(hasMember, SmallAllocator, "resolveInternalPointer")
diff --git a/source/stdx/allocator/building_blocks/stats_collector.d b/source/stdx/allocator/building_blocks/stats_collector.d
index 27f60d2..5eda26f 100644
--- a/source/stdx/allocator/building_blocks/stats_collector.d
+++ b/source/stdx/allocator/building_blocks/stats_collector.d
@@ -160,7 +160,7 @@ struct StatsCollector(Allocator, ulong flags = Options.all,
 private:
     import stdx.allocator.internal : Ternary;
 
-    static string define(string type, string[] names...)
+    enum define = (string type, string[] names...)
     {
         string result;
         foreach (v; names)
@@ -169,7 +169,7 @@ private:
                 ~ "public const("~type~") "~v~"() const { return _"~v~"; }"
                 ~ "}";
         return result;
-    }
+    };
 
     void add(string counter)(sizediff_t n)
     {
diff --git a/source/stdx/allocator/common.d b/source/stdx/allocator/common.d
index a0f5663..776e78f 100644
--- a/source/stdx/allocator/common.d
+++ b/source/stdx/allocator/common.d
@@ -403,7 +403,7 @@ bool alignedReallocate(Allocator)(auto ref Allocator alloc,
 /**
 Forwards each of the methods in `funs` (if defined) to `member`.
 */
-/*package*/ string forwardToMember(string member, string[] funs...)
+/*package*/ enum forwardToMember = (string member, string[] funs...)
 {
     string result = "    import std.traits : Parameters;\n";
     foreach (fun; funs)
@@ -424,7 +424,7 @@ Forwards each of the methods in `funs` (if defined) to `member`.
     }\n";
     }
     return result;
-}
+};
 
 version(unittest)
 {
diff --git a/source/stdx/allocator/gc_allocator.d b/source/stdx/allocator/gc_allocator.d
index a607329..eecdf7e 100644
--- a/source/stdx/allocator/gc_allocator.d
+++ b/source/stdx/allocator/gc_allocator.d
@@ -2,6 +2,14 @@
 module stdx.allocator.gc_allocator;
 import stdx.allocator.common;
 
+version (D_BetterC) {
+    import stdx.allocator.building_blocks.null_allocator;
+    alias GCAllocator = NullAllocator;
+} else
+    version = HasDRuntime;
+
+version (HasDRuntime):
+
 /**
 D's built-in garbage-collected allocator.
  */
diff --git a/source/stdx/allocator/mallocator.d b/source/stdx/allocator/mallocator.d
index b7ffc2a..1ada069 100644
--- a/source/stdx/allocator/mallocator.d
+++ b/source/stdx/allocator/mallocator.d
@@ -201,6 +201,9 @@ version (Windows)
 /**
    Aligned allocator using OS-specific primitives, under a uniform API.
  */
+version (WebAssembly) {} else version = HasMemAlign;
+
+version (HasMemAlign)
 struct AlignedMallocator
 {
     @system unittest { testAllocator!(() => typeof(this).instance); }
diff --git a/source/stdx/allocator/package.d b/source/stdx/allocator/package.d
index 0cd28a8..7ca7c71 100644
--- a/source/stdx/allocator/package.d
+++ b/source/stdx/allocator/package.d
@@ -223,6 +223,10 @@ Source: $(PHOBOSSRC std/experimental/_allocator)
 
 module stdx.allocator;
 
+version (D_BetterC) {} else version = HasDRuntime;
+
+version (HasDRuntime):
+
 public import stdx.allocator.common,
     stdx.allocator.typed;
 
diff --git a/source/stdx/allocator/showcase.d b/source/stdx/allocator/showcase.d
index acc0b34..a73bd44 100644
--- a/source/stdx/allocator/showcase.d
+++ b/source/stdx/allocator/showcase.d
@@ -7,6 +7,10 @@ facilities, or import individual heap building blocks and assemble them.
 */
 module stdx.allocator.showcase;
 
+version (D_BetterC) {} else version = HasDRuntime;
+
+version (HasDRuntime):
+
 import stdx.allocator.building_blocks.fallback_allocator,
     stdx.allocator.gc_allocator,
     stdx.allocator.building_blocks.region;