diff --git a/CMakeLists.txt b/CMakeLists.txt
index 294ea22..2e43340 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,6 +33,9 @@ option (pfs_BUILD_TESTS "Build tests" ON)
 
 add_compile_options (-std=c++11 -Wall -Wextra -pedantic -Werror)
 
+# Ensure that off_t is 64-bits even on 32-bit systems
+add_compile_options (-D_FILE_OFFSET_BITS=64)
+
 set (CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/out)
 set (CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
 set (CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
diff --git a/README.md b/README.md
index a20fbfd..1a8d86c 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,7 @@ Run `cmake . && make`
 ### Currently supported CMake configuration flags:
 
 - `CMAKE_BUILD_TYPE=<Debug|Release>`: Standard CMake flags to control build type (DEFAULT: Debug)
+- `pfs_BUILD_32BIT=<ON|OFF>`: ON to compile a 32-bit binary. OFF to compile using the default configuration of your compiler (DEFAULT: `OFF`))
 - `pfs_BUILD_SHARED_LIBS=<ON|OFF>`: ON to compile a shared library. OFF to compile a static library (DEFAULT: Inherit `BUILD_SHARE_LIBS`, which is `OFF` by default))
 - `pfs_BUILD_ASAN=<ON|OFF>`: ON to enable address sanitizer (DEFAULT: `OFF`)
 - `pfs_BUILD_SAMPLES=<ON|OFF>`: ON to build the sample programs (DEFAULT: `ON`)