diff --git a/app/lib/ntext.cpp b/app/lib/ntext.cpp
index c91edb6d..e9ca2982 100644
--- a/app/lib/ntext.cpp
+++ b/app/lib/ntext.cpp
@@ -236,7 +236,7 @@ const char* PositionalNumeralSystem::GetText(double number)
     if (exponent != 0) {
         buf->Append('e');
         buf->Append(exponent > 0 ? '+' : '-');
-        IntegerToBuffer(fabs(exponent), 3, &digitout);
+        IntegerToBuffer(abs(exponent), 3, &digitout);
     }
 
     // Make sure no rounding error is returned
@@ -447,7 +447,7 @@ const char* DecimalSystem::GetRealText(double value)
     while (buf->RemoveTrailing('0'))
         ;
     buf->RemoveTrailing(fractionpoint);
-    delete out;
+    delete[] out;
 
     return buf->GetString();
 }
diff --git a/app/main/lexer.cpp b/app/main/lexer.cpp
index 19bca497..5f524fe1 100644
--- a/app/main/lexer.cpp
+++ b/app/main/lexer.cpp
@@ -45,7 +45,7 @@ Lexer::~Lexer()
     delete [] input;
 
     if (first != NOMEM) {
-        delete first;
+        delete [] first;
     }
 }
 
@@ -205,7 +205,7 @@ bool Lexer::GetDigitValue()
     *(text + len) = '\0';
 
     current = new Token(current, symnumber, text, pos);
-    delete text;
+    delete [] text;
     delete number;
 
     pos += len;
diff --git a/app/system/language.cpp b/app/system/language.cpp
index 80fca41f..d392dd74 100644
--- a/app/system/language.cpp
+++ b/app/system/language.cpp
@@ -156,7 +156,7 @@ char* Language::UntagText(const char* text)
     unsigned int len = StrLen(untagged) + 1;
     lastText = new char[len];
     MemCopy(lastText, untagged, len);
-    delete untagged;
+    delete [] untagged;
 
     return lastText;
 }
diff --git a/app/system/language_posix.cpp b/app/system/language_posix.cpp
index f60e0a53..f6adb6ef 100644
--- a/app/system/language_posix.cpp
+++ b/app/system/language_posix.cpp
@@ -98,7 +98,7 @@ bool PosixLanguage::StrIsEqualLoc(const char* s1, const char* s2)
     char *tmp = new char[len];
     strxfrm(tmp, s2, len);
     bool res = StrIsEqual(s1, tmp);
-    delete tmp;
+    delete [] tmp;
     return res;
 }
 
diff --git a/app/system/preferences_stdc.cpp b/app/system/preferences_stdc.cpp
index c2585db7..9d71e325 100644
--- a/app/system/preferences_stdc.cpp
+++ b/app/system/preferences_stdc.cpp
@@ -65,7 +65,7 @@ bool StandardPreferences::Load()
         }
     } while (c != NULL);
 
-    delete buf;
+    delete [] buf;
     fclose(file);
     SetPrefs(text->GetString());
     delete text;
diff --git a/lib/real/pow.c b/lib/real/pow.c
index 89792573..3f02fd51 100644
--- a/lib/real/pow.c
+++ b/lib/real/pow.c
@@ -42,9 +42,12 @@
 #include "prim.h"
 #include "math.h"
 
-#if __GNUC__ > 2
-#pragma GCC diagnostic ignored "-Wunused-but-set-variable"
-#pragma GCC diagnostic ignored "-Wstrict-aliasing"
+#ifdef __clang__
+# pragma clang diagnostic ignored "-Wunused-variable"
+# pragma clang diagnostic ignored "-Wstrict-aliasing"
+#elif defined(__GNUC__) || defined(__GNUG__) && __GNUC__ > 2
+# pragma GCC diagnostic ignored "-Wunused-but-set-variable"
+# pragma GCC diagnostic ignored "-Wstrict-aliasing"
 #endif
 
 static const double