fix warnings: expression result unused [-Wunused-value]

In the assert()s take advantage of the fact that string constants
("string") are effectively of type 'const char []', which when used in
an expression yield a non-NULL pointer.

An assertion that should always fail can thus be formulated as:
  assert(!"fail);

An assertion where a text message should be added to the expression can
be written as such:
  assert("message" && expression);

Signed-off-by: Giel van Schijndel <me@mortis.eu>

src/db.h

@@ -88,7 +88,7 @@ protected:
         if (!pdb)
             return false;
         if (fReadOnly)
-            assert(("Write called on database in read-only mode", false));
+            assert(!"Write called on database in read-only mode");
 
         // Key
         CDataStream ssKey(SER_DISK);
@@ -117,7 +117,7 @@ protected:
         if (!pdb)
             return false;
         if (fReadOnly)
-            assert(("Erase called on database in read-only mode", false));
+            assert(!"Erase called on database in read-only mode");
 
         // Key
         CDataStream ssKey(SER_DISK);

src/main.cpp

@@ -1688,7 +1688,7 @@ string GetWarnings(string strFor)
         return strStatusBar;
     else if (strFor == "rpc")
         return strRPC;
-    assert(("GetWarnings() : invalid parameter", false));
+    assert(!"GetWarnings() : invalid parameter");
     return "error";
 }
 

src/script.h

@@ -486,7 +486,7 @@ public:
     {
         // I'm not sure if this should push the script or concatenate scripts.
         // If there's ever a use for pushing a script onto a script, delete this member fn
-        assert(("warning: pushing a CScript onto a CScript with << is probably not intended, use + to concatenate", false));
+        assert(!"warning: pushing a CScript onto a CScript with << is probably not intended, use + to concatenate");
         return *this;
     }
 

src/util.h

@@ -264,7 +264,7 @@ public:
 // I'd rather be careful than suffer the other more error prone syntax.
 // The compiler will optimise away all this loop junk.
 #define CRITICAL_BLOCK(cs)     \
-    for (bool fcriticalblockonce=true; fcriticalblockonce; assert(("break caught by CRITICAL_BLOCK!", !fcriticalblockonce)), fcriticalblockonce=false)  \
+    for (bool fcriticalblockonce=true; fcriticalblockonce; assert("break caught by CRITICAL_BLOCK!" && !fcriticalblockonce), fcriticalblockonce=false)  \
     for (CCriticalBlock criticalblock(cs); fcriticalblockonce && (cs.pszFile=__FILE__, cs.nLine=__LINE__, true); fcriticalblockonce=false, cs.pszFile=NULL, cs.nLine=0)
 
 class CTryCriticalBlock
@@ -278,7 +278,7 @@ public:
 };
 
 #define TRY_CRITICAL_BLOCK(cs)     \
-    for (bool fcriticalblockonce=true; fcriticalblockonce; assert(("break caught by TRY_CRITICAL_BLOCK!", !fcriticalblockonce)), fcriticalblockonce=false)  \
+    for (bool fcriticalblockonce=true; fcriticalblockonce; assert("break caught by TRY_CRITICAL_BLOCK!" && !fcriticalblockonce), fcriticalblockonce=false)  \
     for (CTryCriticalBlock criticalblock(cs); fcriticalblockonce && (fcriticalblockonce = criticalblock.Entered()) && (cs.pszFile=__FILE__, cs.nLine=__LINE__, true); fcriticalblockonce=false, cs.pszFile=NULL, cs.nLine=0)