diff --git a/ChangeLog.md b/ChangeLog.md
index c6e16311..4513e999 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -2,7 +2,7 @@
 
 ## Next version
 
-*tbd*
+- Add `which?` utility method, that checks if a executable is available.
 
 ## Current and previous versions
 
diff --git a/build-cfg.yaml b/build-cfg.yaml
index 383112e2..5e17b42b 100644
--- a/build-cfg.yaml
+++ b/build-cfg.yaml
@@ -7,6 +7,7 @@ sources:
   - exts/string
   - exts/hash
   - exts/pathname
+  - exts/mkmf
   - exts/thor
   - core/io
   - grammars/base_lexer
diff --git a/build/fizzy b/build/fizzy
index 30417e9a..5f4ff52d 100755
--- a/build/fizzy
+++ b/build/fizzy
@@ -55,6 +55,7 @@ require "shellwords"
 require "strscan"
 require "uri"
 require "yaml"
+require "mkmf"
 
 # Try to require `thor` or raise an exception.
 begin
@@ -174,6 +175,13 @@ class Pathname
 
 end
 
+# ☞ Exts → Mkmf ────────────────────────────────────────────────────────────────
+
+module MakeMakefile::Logging
+  # Turn off output on `mkmf` methods.
+  @quiet = true
+end
+
 # ☞ Exts → Thor ────────────────────────────────────────────────────────────────
 
 class Thor
@@ -633,6 +641,10 @@ module Fizzy::Environment
 
   include Fizzy::IO
 
+  def which?(name)
+    find_executable(name.to_s)
+  end
+
   # Return the environment variable matching the provided `name`.
   #
   def get_env(name, default: nil)
diff --git a/mkmf.log b/mkmf.log
new file mode 100644
index 00000000..d00e02c4
--- /dev/null
+++ b/mkmf.log
@@ -0,0 +1,4 @@
+find_executable: checking for clang... -------------------- yes
+
+--------------------
+
diff --git a/src/core/environment.rb b/src/core/environment.rb
index 56c39988..78e25edc 100644
--- a/src/core/environment.rb
+++ b/src/core/environment.rb
@@ -4,6 +4,10 @@ module Fizzy::Environment
 
   include Fizzy::IO
 
+  def which?(name)
+    find_executable(name.to_s)
+  end
+
   # Return the environment variable matching the provided `name`.
   #
   def get_env(name, default: nil)
diff --git a/src/exts/mkmf.rb b/src/exts/mkmf.rb
new file mode 100644
index 00000000..50fc30a5
--- /dev/null
+++ b/src/exts/mkmf.rb
@@ -0,0 +1,4 @@
+module MakeMakefile::Logging
+  # Turn off output on `mkmf` methods.
+  @quiet = true
+end
diff --git a/src/requires.rb b/src/requires.rb
index 14b9089e..fe1bfc8b 100644
--- a/src/requires.rb
+++ b/src/requires.rb
@@ -11,6 +11,7 @@
 require "strscan"
 require "uri"
 require "yaml"
+require "mkmf"
 
 # Try to require `thor` or raise an exception.
 begin