Enabled IPO optimizations for official RPM package.

Fixed small mistake in README.md file.

README.md

@@ -20,7 +20,7 @@ This is the complete source code and the build instructions for the Kepka's alph
  - remove some Qt and custom types in favor of using C++ Standard Library types and classes;
  - clang-format;
  - fix almost all warnings;
- - optional inter-procedural optimizations on \*nix (enabled using CMake's `-DENABLE_IPO:BOOL=ON` flag; improves performance but could degrade compile times);
+ - optional inter-procedural optimizations on \*nix (can be enabled by forwarding CMake's `-DENABLE_IPO:BOOL=ON` flag; improves performance but could significantly increase compilation times);
 * Ability to toggle "typographical" replaces (like replace << to « and another);
 * Packages for Fedora and Arch Linux (packages for Debian and Ubuntu will be done soon);
 * UI based on 1.1.21 before UI "mobilization" which degrades UX (e.g. group settings will be accessible from 5 clicks);

kepka.spec

@@ -1,5 +1,6 @@
-# Allow to use Clang compiler...
+# Setting some build conditions...
 %global clang 0
+%global ipo 1
 
 # Applying workaround to RHBZ#1559007...
 %if 0%{?clang}
@@ -81,7 +82,13 @@ export CXX=clang++
 
 # Configuring application...
 pushd %{_target_platform}
-    %cmake -G Ninja -DPACKAGED_BUILD=1 -DCMAKE_BUILD_TYPE=Release ..
+    %cmake -G Ninja \
+    -DPACKAGED_BUILD:BOOL=ON \
+%if 0%{?ipo}
+    -DENABLE_IPO:BOOL=ON \
+%endif
+    -DCMAKE_BUILD_TYPE=Release \
+    ..
 popd
 
 # Building application...