diff --git a/dmd2/expression.c b/dmd2/expression.c
index 35c24208..3a866751 100644
--- a/dmd2/expression.c
+++ b/dmd2/expression.c
@@ -1881,7 +1881,18 @@ void floatToBuffer(OutBuffer *buf, Type *type, real_t value)
     if (r == value)                     // if exact duplication
         buf->writestring(buffer);
     else
-        buf->printf("%La", value);      // ensure exact duplication
+    {
+#ifdef __HAIKU__	// broken printf workaround
+        char buffer2[25];
+        char *ptr = (char *)&value;
+        for(int i = 0; i < sizeof(value); i++)
+            snprintf(buffer2, sizeof(char), "%x", ptr[i]);
+
+        buf->writestring(buffer2);
+#else
+        buf->printf("%La", value);	// ensure exact duplication
+#endif
+    }
 
     if (type)
     {
diff --git a/dmd2/lexer.c b/dmd2/lexer.c
index e6da85a5..3f41618e 100644
--- a/dmd2/lexer.c
+++ b/dmd2/lexer.c
@@ -12,6 +12,8 @@
 #include <cmath>
 #endif
 
+#include <sstream>
+
 /* Lexical Analyzer */
 
 #include <stdio.h>
diff --git a/dmd2/mars.h b/dmd2/mars.h
index c98ebfed..61ae0390 100644
--- a/dmd2/mars.h
+++ b/dmd2/mars.h
@@ -153,6 +153,7 @@ enum OS
 {
     OSinvalid,
     OSLinux,
+    OSHaiku,
     OSWindows,
     OSMacOSX,
     OSFreeBSD,
diff --git a/dmd2/root/port.c b/dmd2/root/port.c
index 49794cc8..d4b20696 100644
--- a/dmd2/root/port.c
+++ b/dmd2/root/port.c
@@ -315,7 +315,7 @@ char *Port::strupr(char *s)
 
 #endif
 
-#if linux || __APPLE__ || __FreeBSD__
+#if linux || __APPLE__ || __FreeBSD__ || __HAIKU__
 
 #include <math.h>
 #if linux
@@ -368,11 +368,15 @@ PortInitializer::PortInitializer()
 #endif
 }
 
+#ifndef __HAIKU__
 #undef isnan
+#endif
 int Port::isNan(double r)
 {
 #if __APPLE__
     return __inline_isnan(r);
+#elif defined __HAIKU__
+    return isnan(r);
 #else
     return ::isnan(r);
 #endif
@@ -382,6 +386,8 @@ int Port::isNan(long double r)
 {
 #if __APPLE__
     return __inline_isnan(r);
+#elif defined __HAIKU__
+    return isnan(r);
 #else
     return ::isnan(r);
 #endif
@@ -414,6 +420,8 @@ int Port::isInfinity(double r)
 {
 #if __APPLE__
     return fpclassify(r) == FP_INFINITE;
+#elif defined __HAIKU__
+    return isinf(r);
 #else
     return ::isinf(r);
 #endif
diff --git a/dmd2/root/port.h b/dmd2/root/port.h
index d773c128..b4e7fbb7 100644
--- a/dmd2/root/port.h
+++ b/dmd2/root/port.h
@@ -40,7 +40,7 @@ struct Port
     static double dbl_min;
     static long double ldbl_max;
 
-#if __GNUC__
+#if __GNUC__ && !defined __HAIKU__
     // These conflict with macros in math.h, should rename them
     #undef isnan
     #undef isfinite
diff --git a/dmd2/root/root.c b/dmd2/root/root.c
index 0ff5a461..6cd0ea64 100644
--- a/dmd2/root/root.c
+++ b/dmd2/root/root.c
@@ -34,6 +34,10 @@
 #include <errno.h>
 #endif
 
+#ifdef __HAIKU__
+#include <iostream>
+#endif
+
 #if POSIX
 #include <sys/types.h>
 #include <sys/stat.h>